DIPLOSIS PTRIVORA, THE PEAR -GNAT. 



131 



which it gives off its descending branch, which turns down at 

 ahnost a right angle, and runs in a straight line to the border ; 

 after emitting this branch the anal vein turns abruptly a little 

 u^Dwards, and then forwards and downwards, and is continued 

 in nearly a straight course to the margin, which it reaches at a 

 point nearly equidistant between the end of its lower branch and 

 the end of the cubital (see iig.). Legs brown, clothed with white 

 hairs, which are more dense on their under surfaces, and more 

 numerous on the femora and tibiae than on the tarsi ; the 

 tibiai look quite pale in certain aspects, while the knees and tarsi 

 look dark. 



In conclusion, I must make a few remarks respecting the 

 larva of this Diplosis. Like other Cecid. larvae, it has 14 joints 

 or segments (those of most insects have only 13), 

 the supernumerary joint being placed between 

 the head and the first thoracic segment. The 

 sternum {spatula sternalis, Mik ; anchor-shaped 

 process, Ormerod), a horny body, which seems 

 to be peculiar to the larvsG of this family, is 

 placed on the under side of the body, near the 

 junction of the first thoracic segment, with the 

 supernumerary one. It is a more or less elon- 

 gated process, with a widened head, which varies 

 in shape in different species. The head is free, 

 and projects forward; while the posterior end 

 or root is fixed, and partly concealed beneath 

 the semitransparent skin of the first segment. 

 The larva of D. pyrivora, being of a whitish 

 yellow colour, this process can be easily seen, for it is bright 

 pink. As the form of this organ is of diagnostic importance, I 

 have appended a figure, showing its shape and position. The 

 fore part of the larva has been elongated by pressure under the 

 microscope, and therefore looks too tapering. 



Bradfonl, Marcli ^9, 1888. 



Fig. showing 

 sternal process 

 on under side of 

 larva of Diplosis 

 pyrivora. 



