CADDIS-FLIES. 91 



type, as is the rest of the thorax, especially the coxge and 

 side-pieces (pleurites); while the long, slender abdomen re- 

 calls the shape of that of moths. Moreover, the body and 

 wings, usually hairy, are sometimes covered with scales; and 

 the venation is somewhat as in moths. 



The transformations are much as in those of the lower 

 moths, though in the pupa the limbs are free, not soldered 

 to the body as in moths. The larva?, which breathe by 

 means of thread-like tracheal gills, construct cases of bits 

 of sticks, or grains of sand, which they drag over the bot- 

 tom of quiet pools ; they live both on decaying leaves and 

 small insects, water-fleas, etc. When about to pupate they 

 close the mouth of the case with a grating, or, as in Helico- 

 psyche, with a dense silken lid having a single slit, and in 

 some instances spin a slight, thin, silken cocoon, within 

 which the pupa state is passed. The female lays her eggs in 

 clumps covered with jelly on stones and leaves at the water's 

 edge. 



Super family Phryganidae. This great group is divided by McLach- 

 lan into seven families, chiefly according to the structure of the max- 

 illary palpi, as follows: Hydroptilidce, Rhyacophilidip, Hydropsychidte, 

 Leptoceridce, Sericoslomntidiv, Liinnophilidce, and Phryganidce. " In 

 the Rhyacophilid and Hydropsychidw the larvae inhabit fixed cases; in 

 the others the cases are free, and carried about by the inmates. In the 

 Rhyacophilidiv the pupa is enveloped in a special cocoon." (McLach- 

 lan.) 



ORDER XII. COLEOPTERA* (Beetles). 

 Although so numerous in species, upwards of 100,000 



* SELECTED WORKS. 



Dejean et Aube. Species generates de Coleopteres (6 vols., 8vo. Paris, 

 1825-38). 



Gemminger and Harold. Catalogue of all described Coleoptera with 

 synonyma (12 vols. Munich, 1868-76). (Lat.) 



Henshaw, S. List of the Coleoptera of North America. 1885. Supple- 

 ment, pp. 8. 1887 



The entomological writings of John L. LeConte (Cambridge, 



1878). 



The entomological writings of George H. Horn (Cambridge, 



1879). 

 Horn, G. H. Revision of North American Tenebrionidae (Trans. 



Am. Phjl. Soe., 1870). 



Synopsis of Paruid* (Trans. Am. Ent. Soc., ii., 1870). 



(Continued on next page.} 



