Life-Jusior>/ of DasyhelcA ohscma, Wiunertz. 579 



(a) The Head. 



The head of the larva is of a dark brown colour, triangular 

 in shape, 330 /i long and 175 yu- wide in its basal ])ortion 

 (PI. XIX. fig. 1). Examined from the dorsal side, it shows 

 clearly the suture which marks the dorsal plate or clypeus, 

 which, in the skin cast at the moults, is very easily separated 

 from the rest of the head, and then shows two pairs of short 

 sensory hairs emerging from the edges of its anterior 

 portion (text-fig. 2, B, / and g). The head bears a definite 

 number (14 pairs) of sensory hairs and pits, the distribution 

 of which is shown in fig. 1 (PI. XIX.). 



The erjes are heavily pigmented and crescent-shaped. 



Text-fi-. 2. 



A, maudibule of tlie larva of D. obscura ; B, its clypeus. 



The antennce [a and PI. XIX. fig. 5) are very small and 

 situated near the anterior end of the head ; they are com- 

 posed of a basilar segment bearing a special sensory organ 

 corresponding to the bell-shaped papillae of the antennre 

 of many other Dipterous larvte. The basal segment shows, 

 moreover, a short protuberance provided with four cylindrical 

 papillae. 



The labrum, which follows the clypeal plate, is very sliort. 

 Its dorsal side (PI. XX. fig. 10) shows a pair of sensory hairs 

 and a pair of sensory circular pits. The ventral side is of a 

 more complicated structure (PI. XIX. fig. 2) ; it is provided 



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