^i^^^^^Lby 



a Mxp 



Mx' 



Fig. g6.— Diagram of mouth-parts 

 of Lepidopterous insect. The iden- 

 tity of the parts marked Mn^ with 

 true mandibles has been questioned. 



SHORT CHARACTERS OF ORDERS OF INSECTS 187 



Order Trichoptera (caddis-flies). Mandibles vestigial in 

 adult. There are two pairs of fringed wings with compara- 

 tively few veins, the hind pair 

 often larger and folded longi- 

 tudinally. Larva aquatic, usually 

 living in a case of its own con- 

 struction. 



Order Lepidoptera (moths 

 and butterflies). Mouth - parts 

 suctorial in adult, if functional ; 

 the maxillsE forming a spirally 

 wound proboscis. There are 

 usually two pairs of wings, covered 

 with minute scales, and pro- 

 vided with few transverse veins. 

 The larva is a caterpillar. 



Order Diptera (flies, gnats, midges, fleas). Mouth-parts 

 of adult usually adapted for piercing and sucking, often with 



a labial proboscis. 

 / \ Lbr A fore pair of trans- 



parent functional wings, 

 often with scattered 

 scales, and a pair of 

 vestigial hind wings 

 (halteres). Larva foot- 

 less, or with pseudo- 

 pods only. Fleas are 

 probably aberrant wing- 

 less Diptera. 



Order Coleoptera (beetles). Mouth-parts biting, very 

 rarely sucking. The fore wings are nearly always dense, and 

 form wing-covers (elytra) which meet accurately along a straight 

 line • they are sometimes soldered ; the hind pair membranous, 

 and folded both longitudinally and transversely m most cases, 

 sometimes reduced or wanting. 



Order Strepsiptera (internal parasites of bees and wasps;. 

 Mouth-parts vestigial. There are two pairs of wings in the 

 male, the fore pair vestigial and roUed-up at the tip, the 

 hind pair large ahd folded fanwise; the female is wingless. 

 Strepsiptera are often regarded as aberrant Coleoptera. 

 Order Hymenoptera (saw-flies, wasps, bees, ants, ichneumon- 



Ep 



I Mn 



Mx 



pjg^ gy. — Diagram of mouth-parts of 

 Dipterous insect (gadfly). 



