SPONGILLA-FLIES — PARFIN AND GURNEY 441 



srtarated from the sisyrid larvae, with which they appear to be 

 csely alhed, by the following characteristics: No tracheal gills in 

 ay instar; antennae 3-segmcnted, shorter than jaws in all instars; 

 jirs curved slightly upwards and outwards; two transverse rows of 

 siae on meso thorax, metathorax, and first eight abdominal segments; 

 a:l tenth segment with pair of eversible processes covered with 

 r urved hooks (fig. 3,c). 



A.S in all Neuroptera (sensu strictu), the food of the larva is almost 

 etirely fluid, and is sucked up through two tubes or canals formed by 

 t ^ closely appressed maxillae and mandibles, which are grooved on 

 tiir inner surfaces. Each mandibulomaxillary canal so formed is 

 oen distally near the apex and proximally near the base (fig. 3,f,j). 

 I transverse cleft ("mouth" in Myrmeleon formicarius, Lozinski, 

 138, p. 477) between the bases of the jaws is kept shut by the close 

 aposition of the labrum into a depression of the labium as pointed 

 ct in Myrmeleon by Lozinski and in Dytiscus (Coleoptera) by Snod- 

 giss (1935, p. 287). The preoral food cavity (cibarium) just within 

 t3 cleft is open not only at each end at the basal apertures of the 

 cnals but also internally at the true mouth (Snodgrass) leading into 

 te stomodaeum. The anterior part of the stomodaeum is the phar- 

 \x, and it is the sucking pump with dilator and compressor muscles 

 aached to it in Myrmeleon (the "pharyngeal pump" of the Neu- 

 iptera as of Withycombe, 1925, p. 368). Withycombe (1923, p. 503) 

 seaks of the mouth being closed by a membrane or integument of the 

 lad immediately after hatching. The membrane is later retracted 

 ito the head. This bears investigation, since it may possibly be a 

 (ndition present in other insects. 



The midgut is a large sac closed at the posterior end and occupying 

 1e anterior two-thirds of the abdomen. The small amount of solid 

 uste appears to be stored up in the posterior end of the midgut and 

 (■posited as a fecal pellet in a peritrophic membrane after the emer- 

 ince of the adult. 



The hind gut in Sisyra vicaria seems to be closed to any appreciable 

 issage of solid excrement and to consist of almost a solid cord of 

 rophied cells that ends in the walls of a dilated silk receptacle, lead- 

 :,g to the rectum, anus and spinneret, according to Anthony (1902, 

 0. 623-625). The thin walls of the silk receptacle have a cellular 

 iructure, similar to that of the Malpighian tubules from which the 

 ik is spun through the anus. When the larva is about ready to 

 Crete silk, the tubules are modified in their middle portions by the 

 :esence of larger, more irregularly shaped cells with ramified nuclei, 

 he five tubules of vicaria (Anthony, 1902, p. 623) are attached at 

 ,ieir anterior ends to the junction of the hind gut and midgut — with 

 iree of them also attached at the posterior end (apparently to the 



