THE PITCH MIDGE 797 



body of one of the leaf-miniug larvse. They are pale milk-white in color, and the 

 alimentary canal blackish ; they are long and slender in form. A very small Ta- 

 chiua fly was also bred, both from the northern and southern specimens. (Comstock 

 in Agricultural Report for 1879.) 



We have found at Brunswick, Me., young pitch-pine trees the leaves 

 of which had been attacked by this larva; the injury was quite local, 

 not general. We found larvte April 4, 1883, on the outside of the leaves 

 of P. rigida, on leaves affected last year, boring in the needles near the 

 middle. This is the only Tineid recorded, as far as we know, as living on 

 the pine, which seems remarkably free from the attacks of this family. 



127. The pitch-inhabiting midge. 



Diplosis resinicola Osten-Sacken. 



Order Diptera ; family Cecidomvid.e. 



Feeding early in May, and again towards the middle of June, in companies of 

 thirty or forty, in the pitch exuding from wounds in the bark of the pitch-pine, 

 small, slender, footless, orange larvse, changing to two-winged midges or gall-flies 

 late in May and the middle of June. (Comstock.) 



The following account of this interesting fly is taken from Professor 

 Comstock's Report for 1879 : 



In 1868, Mr. Sanborn exhibited before the Boston Society of Natural History speci- 

 mens of a " Cecidomyious larva," which he had found feeding in companies of thirty 

 or forty in the pitch exuding from wounds in the bark of Pinus rigida. '• Whether 

 they were the prime cause of the injury to the tree was not plainly apparent." (See 

 Proceedings Bost. Soc. Nat. Hist., xil, p. 93. ) In the Proceedings of the Entomological 

 Society of Philadelphia, 1871, p. 345, Osten-Sacken records the discovery of similar 

 larvjB in the exuding resin of Pinus inops at Tarrytown, N. Y. These he reared to 

 the perfect state, and gave the species the name of Diploais resinicola. 



Early in May the two-or-three-year-old branches of Pinus inops in the vicinity of 

 Washington were observed to be quite extensively infested by these insects, which 

 were then in the larva state and actively feeding. They shortly turned to pupae, and 

 the first midge emerged May 26. On June 11 larvae of the same species were found 

 upon the twigs of Pinus rigida at Ithaca, N. Y. Pupte were also found in the same 

 twigs, and June 13 the first midge issued. In February, 1880, I collected specimens 

 of similar larvae at Orange Lake, Florida, on twigs of Pinus tceda, which, upon the 

 appearance of the adults on March 1, were found to be of the same species. 



Fig. 87 (from Comstock) shows well the work of this insect. The lumps of exuding 

 resin may contain from two to thirty of the larvae, which, when full-grown, measure 

 on an average e""™ (about one-quarter of an inch) in length. While still feeding they 

 are pale-orange in color, but after ceasing they become of a bright orange. The 

 spiracles of the anal segment are at the summit of two protruding tubercles, and 

 around each is a small whorl of four fleshy papilhe. The other spiracles are small 

 and black. The larvae are much elongated, and are widest at the 6th segment ; the 

 undersides of segments 1 to 7 are furnished each with two transverse rows of short 

 black or brown spines, probably for locomotive purposes. While burrowing in the 

 bark and resin the anal tubercles are always at the surface. When, however, the 

 larva contracts to pupate, the end of the body is drawn in, but an open channel is 

 left so that the air has free access. When about to give out the adult, the pupa 

 works its way to the surface of the resin and protrudes half its body, so that there is 

 no danger of the midge becoming fastened in the sticky gum. Dried lumps of resin. 



