488 SYNOPTIC COLLECTION. 



Tabanus lineola Fabr., but first the characters of the more 

 generalized Diptera, the Orthorhapha, must become fa- 

 miliar. 



The Tipulidae, represented by the crane-flies, have 

 cylindrical, colorless, footless larvae (PI. 1248, fig. i, Tip 

 ula eluta Loew), proving that even in these most general- 

 ized members of the order the Thysanuriform larval 

 stage is wholly skipped. The larvae, however, have 

 horny mandibles for biting ; they also have tubercles in 

 place of feet. 



The pupa (fig. 2) is free; that is, it is not enclosed in 

 the hardened larval skin, the puparium, but is naked and 

 the thoracic appendages are clearly seen. In this stage 

 the respiratory tubes extend from the prothorax. 



The adult Tipula (No. 1249) has a long body with 

 the thoracic segments extended and plainly visible (PI. 

 1250, fig. i, dorsal view of thorax of Tipula; fig. 2, side 

 view of same). 



The feeble legs are extremely long. The wings are 

 reduced to one pair, the second pair of most insects act- 

 ing as balancers or poisers. Proof that the balancers 

 were originally wings is found in the fact that in the 

 pupal stage of several species of Diptera these organs 

 are large and broad. 



The Tipulidae, like all Diptera, are without a sting, 

 and, as one might expect, the abdomen is not peduncu- 

 lated. Tipula, however, like the more generalized insects, 

 has an external ovipositor with which it makes holes in 

 earth, fungi, and the like for its eggs. 



One species of this family, Tipula agarici seticornis De 

 Geer, according to De Geer, has two spinnerets for spin- 

 ning silk. 1 



The Culicidae or mosquitoes resemble the Tipulidae 

 in certain adult characters, but the larvae are aquatic. 

 The eggs (PL 1251, fig. i, Culex pungens Wied) are laid 



iRirby and Spence, Introd. to Ent, III, 1826, p. 125. 



