AMERICAN DIITERA. 345 



BIOLOGICAL NOTES ON DIPTE2A, (Article 3d.) 



BY R. OSTEN SACKEN. 



1. A Cecidomijia^ livinp; in pinc-resin {Diplosix resinirnln, n. sp.) 

 On the 28th of May, 1H71, beiug in Tarry town, N. Y., I uotited 

 some lumps of seuii-liquid resin on the smaller limbs of young scrub 

 pines {Finus inoj)s) growing in a garden on the banks of the Hudson 

 River. These lumps where whitish, about half an inch long, or 

 smaller. On trying to remove the resin, I noticed that it harbored a 

 number of reddish maggots; some specimens containing two or three 

 only, others as many as twenty. The maggots had the color of the 

 larv?e of C'ci'hm^ia, but, in some other respects they were different. 

 No lateral spiracles were apparent, but, in their stead, a pair, of horny, 

 approximate dentate tubes at the anal end of the body, not unlike the 

 respiratory tubes of the larvae of Sj/rjihus. The breastbone, usually 

 distinctive of the larvae of Ceculomj/ia, was not apparent. The manner 

 of extending and contracting the body, especially the front part, also 

 reminded one of Sj/rphus. When, after having been disturbed by me, 

 they were left alone for some time, they again buried themselves in 

 the resin, their respiratory tubes alone appearing on the surface of the 

 lump. By counting these, under a magnifying glass, one could easily 

 ascertain the number of the hidden larva). After having brought 

 them home, I noticed after a few days that the larvae had gradually 

 contracted towards the inside of the lump, each however remaining 

 connected with the open air by a tubular passage of apparently hardened 

 resin. Both these tubes and the reddish larvae at their inner end 

 were visible through the semi-transparent resin. 



It was evident that the larvae were undergoing transformation. A 

 few days more, and the reddish color of the pupae became blackened, 

 and on the 11th of June the flies escaped. The process was as follows : 

 the pupa, by gentle contractions and expansions of the abdominal seg- 

 ments gradually pushed itself along its tube towards the surface of the 

 lump, until its thorax projected out of the resin ; then the thorax split 

 open and the fly emerged in the usual manner; the pupa-case re- 

 mained behind, sticking out of the resin. The pupa is quite smooth 

 without any horny projections on its front part. I obtained about 

 twenty flics from a single lump, which, after their escape, looked 

 quite honeycombed by the now empty, vermicular tubes. 



