DIPTERA. 259 



Unlike most Diptera, crane-flies have an external, 

 horny ovipositor, which is used for making holes in 

 earth, mould, fungi, etc., as the larvae of many species 

 are terrestrial. The latter feed upon the tender roots 

 of grass, clover, and grain, having mandibles and max- 

 illae that are more or less horny and adapted for bit- 

 ing.^ They move by means of swellings on the ventral 

 side of the body, which are provided with bristles. 

 According to Williston^ those larvae of the Tipulidae 

 which live on the leaves of plants are " almost like a 

 caterpillar in appearance," some species being green, 

 with tubercles along the back. It is also stated by 

 Kirby and Spence^ that one species of Tipula (7". 

 Agarici sefico7mis, DeGeer) is provided with two sepa- 

 rate spinnerets. While the Tipulid larvae resemble in 

 these respects the more generalized larval forms of the 

 Lepidoptera and Hymenoptera, they are like the spe- 

 cialized larvae of the last-named group in not possess- 

 ing either thoracic legs or abdominal prop-legs. The 

 pupae of this family are not covered by a puparium, 

 but are free or obtected. 



CULICID.^. 



Mosquitoes have a long body, like crane-flies ; the 

 head is small, the thorax is not so elongated as in the 

 Tipuhdae, although it is wholly exposed, and the abdo- 

 men is slender. The mouth parts, like those of the 

 horse-fly, are well developed. The female feeds upon 



1 See " The Meadow Maggots or Leather Jackets," Sixteenth 

 Report Noxious and Beneficial Insects of Illinois^ 1887-88. 

 - Stand. Nat. Hist., Vol. II., p. 415. 

 3 Introdtiction to Ento?nology, Vol. III., p. 125. 



