36 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



17. Wings two (or wanting). Rear wings represented by 



halteres; wings and body naked or covered with 

 scattered hairs; mouth a soft or horny beak not 



coiled under head 18 



Wings four (sometimes wanting in females). Wings 

 and body covered thickly with scales or hairs ; mouth, 

 when developed, a slender sucking proboscis coiled 

 under the head LEPIDOPTERA 



18. Prothorax poorly developed, scarcely visible from 



dorsal side. Usually two wings DIPTER A 



Prothorax well developed, distinctly visible from dorsal 

 side ; wings never present SIPHON APTERA 



The following arrangement of the orders is in the main 

 that of Comstock, modified in the Neuropteroid groups by 

 Banks, and runs from the lowest to the highest forms. This 

 sequence could not be carried out exactly in the key, but should 

 be followed in the arrangement of insect collections. The 

 principal orders are illustrated by typical examples in Plates 

 III-V. 



THYSANURA. Spring-tails, bristle-tails, and fish moths. 

 A small order, and the insects are mostly of small size, inhabit- 

 ing moist, decaying vegetable matter. 



ODONATA. Dragon-flies and damsel-flies. Plate III. A 

 small or medium-sized order, containing some species of large 

 size. All are aquatic in their larval stages, and feed in both 

 larval and adult stages upon other insects, especially mosquitoes. 

 EUPLEXOPTERA. Earwigs. Plate VII. This order 

 contains only the earwigs, and there are but few species. Many 

 writers treat it as part of the Orthoptera, though it differs 

 structurally. 



ORTHOPTERA. Grasshoppers, crickets, walking-sticks, 

 mantids, and cockroaches. Plates III, VI-XI. This order does 

 not contain a great number of species, but some of them are of 

 larg-e size and therefore noticeable. Nearly all (except the 

 mantids and the crickets) feed upon vegetable food, and some 

 species are very injurious. 



