Larvae for all 4 species of this genus in the Churchill area have been associated. Their larvae can be separated from other limnephilid genera by a combination of: presence of accessory setae on the mesofemur lateral surface; scurf of small, stout spicules on the anterolateral surface of the pronotum absent; and [except for A. rossi (Leonard and Leonard, 1949)] presence of dorsal chloride epithelia. The cases tend to be fairly straight and composed of small mineral particles with occasional small vegetal particles. It appears larvae of the Churchill Asynarchus [unlike Asynarchus contumax (McLachlan, 1880) – see Solem ] convert their case to at least partial mineral material just prior to pupation (see Wiggins ). Flint  also reported vegetal pupal cases for species in this genus.
Asynarchus lapponicus Zetterstedt, 1840 (Figure 8C) is very similar to A. montanus (Banks, 1907). Both have accessory setae on the basal trochantal segment. The gill character is based on examination of two 5th instar larvae of both species. The abdominal ventrolateral gill row of A. lapponicus ends on the 4th segment.
Asynarchus montanus larvae (Figure 8D) are distinguished from A. lapponicus (see discussion above) by the ventrolateral gill row ending on the 6th or 7th abdominal segment.
Asynarchus mutatus (Hagen, 1861) (Figure 8E) can be separated from A. lapponicus and A. montanus by the lack of accessory setae on the basal trochantal segment. Its ventrolateral abdominal gill series also extends to the 6th or 7th segment (n = 2).
Asynarchus rossi has been variously placed in Asynarchus[33, 34] and Limnephilus (Leonard and Leonard 1949, Wiggins  - with Schmid’s concurrence) and presents interesting larval and adult characters. The placement of A. rossi on the Neighbor Joining tree was very far from the rest of the Asynarchus species as well as Limnephilus spp., suggesting a generic revision of the species is needed, although the NJ tree should not be inferred as a phylogenetic relationship for the relevant species. The distinctiveness of A. rossi is also supported by a phylogenetic tree built based on COI and 3 nuclear genes using a Bayesian approach (Boyle, unpublished data). The larvae have several setae on the metanotal membrane between the sa2 sclerites, which are absent in the other Asynarchus, and Limnephilus. Like Limnephilus, A. rossi lacks dorsal chloride epithelia. A. rossi larvae have a very pale yellow head and thorax background color, and, as a result lack the obvious 3-spot frontoclypeus (Figure 8F). In hand, the larvae appear to have a distinct dark, medial thoracic/head stripe. The case is normally comprised of mineral particles and is more curved than that of Asynarchus and Limnephilus.
Limnephilus larvae currently comprise a large, poorly defined genus. This uncertainty in phylogeny is very apparent in the Churchill Limnephilus larvae. Of the 24 Limnephilus species collected at Churchill, larvae of 18 have been associated via DNA. Over the years, major advancements in our ability to separate the North American Limnephilus sensu lato larvae have been largely limited to those of Lloyd , Flint  and Hoopes . The most recent work of Wiggins [21, 37] has greatly improved our ability to separate the Limnephilus sensu lato larvae from the other limnephilid genera although he pointed out that larvae of only 5 North American Limnephilus species had been described at the time. More frequent advances in Holarctic larval Limnephilus taxonomy have occurred, particularly with the work of Lepneva , Hiley , Wallace et al.  and Waringer & Graf . The recent Wallace et al.  publication provides the best summary available today of characters useful for species determinations.
Limnephilus ademus - The larvae of L. ademus belong to the group with both: a dark base colored head with darker muscle scars (Figure 8J); and, accessory setae present on the lateral margins of the meso- and metafemur. The head has two pale blotches primarily outside the anterior constriction of the frontoclypeal suture. A slight pale area is also present in the posterior apex of the frontoclypeal suture. It is most similar to L. major, another member of the L. incisus group. The larva was described by Flint and Giberson  although the figure of the head presented there does not show the pale areas anterior of the eyes shown here, which occurs in the Churchill larvae.
Limnephilus alaicus - The larvae of L. alaicus is another of the group with accessory setae on the lateral margins of the meso- and metafemur. It can be separated from the closely related L. incisus group larva by the anterior pale areas of the head, which are primarily located within the frontoclypeal sutures (Figure 8K). Grigorenko  synonymized L. alaicus, L. pallens (Banks, 1920) (a North American species), and L. tricalcaratus (Mosely, 1936) under L. samoedus (McLachlan, 1880). Malicky  resurrected L. alaicus. It will take further DNA and morphological studies of all taxa within the group to determine which species are valid.
Limnephilus argenteus Banks, 1914 larvae belong to the group of Churchill Limnephilus with the character combination of: head with a dark base color and darker muscle scars (Figure 8L); and, lateral margins of the meso- and metafemur lacking accessory setae. Based on the examined specimens, L. argenteus can be separated from the other Churchill larvae in this group [L. perpusillus Walker, 1852, L. picturatus McLachlan, 1875, L. sericeus (Say, 1824)] by the very monochromatic brown head coloration with little evidence of pale blotches in the frontoclypeal area.
Limnephilus canadensis Banks, 1908 larvae are relatively small, less than 15 mm in length. And the cases are made of medium size mineral particles. There are both dark and light large, primary meso- and metafemur ventral setae with the distal one of the pair pale on the mesofemur and the proximal one pale on the metafemur. The head and thorax have a pale yellow background color with many dark muscle scars (Figure 9A).
Limnephilus externus Walker, 1852 has a distinctive prothoracic color pattern with a large dark band along the anterior margin. The head pattern (Figure 9B) is essentially the same as Nemotaulius hostilus Hagen, 1861. The two primary setae along the ventral meso- and metafemur margins are dark. It is very similar to L. extractus Walker, 1852 but can be separated by the presence of numerous setae at the mesonotal sa1 location.
Limnephilus extractus is another taxa with the characteristic three-band head pattern (Figure 9C) and wide dark band along the anterior margin of the pronotum. It has a single seta at the mesonotal sa1 position (see discussion at L. externus).
Limnephilus femoralis (Zetterstedt, 1840) is one of the four Churchill area taxa with the characteristic three-band head pattern (Figure 9D) and wide dark band along the anterior margin of the pronotum. We had only a single larva for examination. The lateral dark head bands extend to the hind margin of the head in L. femoralis, while ending before the hind margin in the other taxa.
Limnephilus fischeri Ruiter, 1995 has a very pale yellow head (Figure 9E) and prothoracic background color. The head and pronotum have a pattern similar to others of the L. subcentralis group. In the Churchill area, this group has four species (L. fischeri, L. hageni Banks, 1930, L. partitus Walker, 1852, L. sansoni Banks, 1918), which are most easily separated by coloration. The dark mesonotal color makes L. fischeri the easiest to separate from the rest. Its case is made of long, thin vegetal pieces that appear almost spiraled as in Mystacides or Phryganea. The venter of the 1st abdominal segment has very few setae.
Limnephilus hageni larvae are very similar to the rest of the L. subcentralis group larvae (see discussion under L. fischeri). The indistinct postgenal band (Figure 9F) and pale pronotal base color separate L. hageni from the other L. subcentralis group larvae. The cases in the group are also very similar, comprised of long vegetal pieces. In the L. hageni larvae we have, the vegetal pieces are wider than those of L. fischeri although this probably has no diagnostic significance.
Limnephilus infernalis (Banks, 1914) has a head and pronotal color pattern (Figure 9G) similar to L. externus and L. femoralis. However, L. infernalis has accessory setae on the meso- and metafemur. The dorsoposterior half of the pronotum lacks obvious muscle scars in L. infernalis, while these dark muscle scars are obvious in both L. externus and L. femoralis.
Limnephilus major, like the other L. incisus group larva of the Churchill area (see L. ademus discussion above), has a solid brown background color to the head with darker muscle scars and only pale frontoclypeal markings (Figure 9H). It lacks dorsal chloride epithelia. However, it possesses accessory setae on the lateral surfaces of the meso- and metafemur. The case is made of sand grains and seems quite fragile, and readily crushed. On one specimen we looked at the pale frontoclypeal areas were extremely faint.
Limnephilus nigriceps (Zetterstedt, 1840) has a head and thoracic color pattern very similar to the three-banded head with wide anterior dark pronotal band. However, the head bands are nearly coalesced in most specimens to the point the head appears to have a three-spot pattern (Figure 9I). L. nigriceps, along with L. infernalis, differ from the other three-banded head taxa by possessing accessory setae on the meso- and metafemur lateral surfaces. The larvae of L. indivisus and L. rhombicus (Linnaeus, 1758) also occur in the Churchill area and are expected to have similar coloration and setation as L. nigriceps and L. infernalis[21, 36, 44]. Limnephilus nigriceps lacks dorsal chloride epithelia. In the Churchill area the case is usually made of small, thin bark pieces haphazardly arranged into a slightly triangular cross section.
Limnephilus partitus (Figure 9J) is very similar to L. hageni and L. sansoni Banks, 1918. In L. partitus, the muscle scars of the pronotal dorsoposterior area are widely scattered and distinct and there are few setae on the first abdominal segment.
Limnephilus perpusillus is another taxa with a plain brown head with darker muscle scars and very little color pattern (Figure 9K), and no accessory setae on the meso- and metafemur lateral surfaces. There is a small white triangle in the posterior apex of the frontoclypeal suture and two poorly developed anterior pale areas originating at the anterior frontoclypeal constriction and extending along the frontoclypeal suture nearly to the labrum. These anterior pale areas are located primarily laterad of the frontoclypeal suture. This color pattern is very similar to that of L. major (see discussion above) and L. picturatus. The ventral apotome of L. perpusillus is long (unlike L. picturatus) nearly extending to the posterior head margin. The case is made of dark vegetal fragments and is very smooth and round with little taper or curve.
Limnephilus picturatus has a yellow/brown head with darker muscle scars and a small pale band following the frontoclypeal suture from the apex to the frontoclypeal constriction (Figure 9L). The ventral apotome is short, barely half the length of the ventral ecdysial suture. The meso- and metafemur lack setae on their lateral surfaces. The case is made of fairly large vegetal pieces.
Limnephilus sansoni is another one of the L. subcentralis group (see L. fischeri discussion above) with the pale yellow head and typical medial dark band on the frontoclypeus (Figure 10A); dark U-shaped band outside the frontoclypeal suture; and dark band in the transverse pronotal depression. The thoracic setae are greatly reduced in number with the thoracic sa1 and sa2 reduced to one or two large setae, often just one. The two major setae of the forefemur ventral margin are not both pale, with the black located distally. The case is similar to others of the group, comprised of long vegetal pieces.
Limnephilus sericeus larvae have a dark brown head with faint, darker muscle scars (see L. argenteus discussion above). There are three obvious pale spots on the frontoclypeus (Figure 10B). These anterior pale areas are located primarily outside the frontoclypeal sutures and do not extend anteriorly much past the eye. This color pattern is similar to L. ademus, from which it can be distinguished by the absence of meso- and metafemur accessory setae. The case is made of vegetal parts arranged in a smooth cylinder. The larva was described by Lepneva .