THE ARTHROPODS 380 



antennae. Over 50,000 species of Lepidoptera are known. 

 Consult Dickerson's "Moths and Butterflies"; Comstock's 

 "How to Know Butterflies"; and Holland's "Butterfly 

 Book " and " Moth Book." 



Coleoptera. Name means sheath wing, referring to the 

 hard anterior wings. Examples : all beetles, weevils, fire- 

 flies, June beetles, blister beetles (" Spanish flies "). Some 

 so-called bugs, e.g., lady-bird " bug " and June " bug," are 

 beetles and not bugs (i.e., not Hemiptera). Front wings of 

 beetles are hard and horny, and often called the elytra. 

 Hind wings are membranous. Complete metamorphosis. 

 It is estimated that over 100,000 species of beetles have been 

 named. 



Diptera. Name means two wings ; hind wings absent. 

 Examples : flies, bot-flies, warble-flies, mosquitoes. Mouth- 

 parts for sucking (as in house-fly) or piercing (as in horse-flies). 

 Complete metamorphosis. Larvae commonly called " mag- 

 gots." Small knobs represent the hind wings. About 40,000 

 species are named. 



Fleas. Parasitic insects, wingless or with rudimentary 

 wings. Formerly considered wingless flies, but now in a 

 special order. 



Hymenoptera. Name means membrane wing, e.g., a bee's 

 delicate wing. Examples : ants, bees, wasps, ichneumons. 

 Mouth-parts for both biting and sucking. Complete meta- 

 morphosis. Four wings, hind pair smaller, few irregular 

 veins. Probably about 30,000 species known. 



Practice in Classification of Insects. (L) Students should ex- 

 amine a set of insects (a mixed lot preserved in wood alcohol or 

 formalin is best) ; and by comparing with above descriptions, and 

 the well-known examples mentioned, assign the specimens to the 

 proper orders. In an hour of time one can learn to identify as to 

 orders the most common insects. The names of genera and species 

 of the very common insects can be found in the large books, such as 

 Comstock's "Manual of Insects," but rarer specimens can only be 

 identified by specialists. 



