212 INSECTS INJURIOUS TO FOREST AND SHADE TREES, 
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 specimens of a “ Cecidomyious larva,” which he had found feed- 
ing 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. 
Soe. Nat. Hist., xii, 93.) In the Proceedings of the Entomological So- 
ciety of Philadelphia, 1871, p. 345, Osten-Sacken records the discovery 
of similar larve 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 
Diplosis resinicola. ager 4 
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 feed- 
ing. They shortly turned to pup, and the first midge emerged May 
26. On June 11 larvee of the same species were found upon the twigs 
of Pinus rigida at Ithaca, N. Y. Pupze were also found in the same 
twigs, and June 13 the first midge issued. In February, 1880, I col- 
lected specimens of similar larvie at Orange Lake, Florida, on twigs of 
Pinus teda, 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 larve, 
which, when full-grown, meas- 
ure on an average 6™™ (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 sum- 
mit of two protruding tubercles, 
and around each isa small whorl 
of four fleshy papille. The 
other spiracles are small and 
black. The larve are much 
elongated, and are widest at the 
6th segment; the under sides of segments 1 to 7 are furnished each 
with two transverse rows of short black or brown spines, probably for 
Jocomotive purposes. While burrowing in the bark and resin the anal 
tubercles are always at the surface. When, however, the larva con- 
tracts 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 
Fig. 87.—The pitch-inhabiting midge.—A fter Comstock. 
