198 D1PTERA OF NORTH AMERICA. 



lamels ; femora and tibiae and the anterior pair of tarsi superiorly 

 black or black-brown ; inferiorly white with a silvery reflection ; 

 the posterior tarsi have the two basal joints black or black-brown 

 superiorly, silvery white inferiorly; the three last joints are silvery 

 white, sometimes with blackish articulations ; wings gray, irides- 

 cent with a dense, blackish-brown pubescence and brown vejins ; 

 cross-vein distinct, very oblique, situated a little before the middle 

 of the first longitudinal vein; second longitudinal as in J*, the 

 third likewise, although almost perpendicular to the posterior mar- 

 gin. Length g 9 0.1 to .0.15. 



15. C. brachynteroides, n. sp. Swelling at the basis of the leaves 

 of the scrub pine (Pinus mops). In consequence of this swelling 

 the pairy leaves diverge, their bases coalesce, and the sheath at 

 the basis of the bunch bursts. In July these swellings contain 

 several small reddish larvae ; in winter I found them empty, but 

 having observed some larva? hanging on cobwebs near these galls, 

 I conclude that they undergo their transformation under ground, 

 and were caught in these cobwebs in the attempt to leave the gall. 



The habits of this Cecidomyia seem to be very like those of C. 

 hrachyntera Schwagr. living at the base of the pairy leaves of the 

 European Pinus sylvestris. Still, the latter produces no gall or 

 swelling whatever, and causes the leaves only to wither; it also 

 goes under ground for transformation. (See Ratzeburg, Forst-In- 

 secten, Vol. Ill, p. 160.) 



16. O. serrulatce 0. S. Deformed terminal buds of the common 

 alder (Abuts serrulata). 



The buds appear enlarged, rounded, pointed at the tip, having 

 from three to five lines in diameter. In autumn they are greenish ; 

 in winter withered, brown, and frequently covered with a whitish 

 efflorescence. Each gall contained in October from two to six red- 

 dish larvae, lodged in the same compartment. In winter the galls 

 are found empty, as the larva? go under ground. By keeping some 

 of these galls, gathered in October, on moist earth, I obtained the 

 fly in the following April. It belongs to the sub-genus Cecidomyia 

 Loew. The description has been drawn from fresh specimens. 



C. serrulatae 0. S. g and 9 . — Head and antenna? brownish ; 

 mouth and palpi paler; antenna? 18-jointed in both sexes; joints 

 verticillate and on moderately long pedicels (J 1 ); subcylindrical, 

 subsessile (9); thorax blackish superiorly, the usual three stripes 



• 



