328 INSECTA. 



appendages, by wliicli they are enabled to gnaw or suck the alimen- 

 tary matters on which they feed. They change their skin to undergo 

 their second metamorphosis. The nymphs are naked, and exhibit 

 several of the external parts of the perfect Insect, which issues from 

 its exuviae, through a slit in the back. 



In our first division we find species Avhose proboscis, always en- 

 tirely (or nearly) salient, with the exterior envelope or the sheath of 

 the sucker solid or almost corneous, projects more or less in the form 

 of a tube or siphon, sometimes cylindrical or conical, and sometimes 

 filiform, and terminates without any remarkable enlargement, the 

 lips being small or confounded with the sheath. The palpi are small. 



Some, that are rapacious, have an oblong body, the thorax nar- 

 rowed before, and the wings incumbent; their proboscis is most com- 

 monly short or but slightly elongated, and forms a sort of rostrum. 

 The antennse are always approximated, and the palpi apparent. 



AsiLus, Lin., 



Where the proboscis is directed forwards. 



They fly with a humming noise, are carnivorous, voracious, and 

 according to their size and power, seize on Flies, Tipula?, Bombi, or 

 Coleopter;«, which they then exhaust by suction. Their larvte have 

 a small squamous head, armed with two movable hooks, live in the 

 earth, and tiiere become nymphs, whose thorax is furnished with den- 

 tated hooks, and the abdomen with small spines. 



In some — AsUici, Lat. — the head is transverse ; the eyes are late- 

 ral and distant, even in the males, and the proboscis is at least as 

 long as the head. The wings have a complete cubital cell, forming 

 an elongated triangle near the internal margin — the last of all — 

 and terminating at the posterior edge. The epistoma is always 

 bearded. . 



Sometimes the tarsi terminate by two hooks, with as many inter- 

 mediate pellets. 



Here, the terminal stilct of the antennse is but slightly apparent, 

 or when it is very distinct, its second and last joint is not prolonged 

 in the form of a seta. 



There are some of these in wliich the antennae are hardly longer 

 than the head; their stilet is barely visible or very short, conical and 

 pointed ; the part of the head from which they arise is not promi- 

 nent, or but slightly so. 



Laphria, Meig., Fab., 

 Where the stilet of the last joint of the antennse, which is either 

 fusiform or resembles a small obtuse head, is not (or barely) visible 

 and where the proboscis is straight *. 



* See Lat., Gen. Crust, et Insect, IV, 298 ; Meig., Fub., Wied., und Macq. 



