1»06 ENTOMOLOGICAL SOCIETY. 59 



Family, Cynipidae. Gall flies. 



This is a family of very minute, four-winged insects. In the adult 

 gall fly tlie abdomen is unusually compressed and joined to the thorax by 

 a short peduncle, the first abdominal segment. The first segment is large 

 and the remaining ones are short and each is more or less covered by the 

 preceding. The ovipositor is long and slender. The insect deposits its eggs 

 within the tissues of the plant by piercing it with its ovipositor. The wings 

 have few veins and the fore-wings lack the stigma. The galls produced are 

 closed and the insect emerges at maturity through a hole which it cuts in 

 the gall. One of the most interesting features of insect life that has been' 

 discovered was noticed by Bassett and confirmed by Adler in regard t« 

 these insects. By careful investigation he discovered that two generations 

 of these insects were produced every year, each of which produced a different 

 sort of gall, and which could not be recognized as the same species. There 

 is still, however, an enormous amount of work to be done upon this subject 

 in America. 



Eriophtidae. 



Eriophyes quadripes. Produces top-shaped galls on the upper surface 

 of the leaves of soft Maple. The galls are greenish at first, then become red, 

 or purplish and finally dark brown. In the younger galls the inside wall 

 is fairly smooth and the interior is hollow. As the galls grow older, irregii- 

 lar and somewhat granular excrescences appear on the interior wall and grow 

 toward the centre until in the older specimens the interior may become quite 

 full. It occurs on Soft Maple (Acer dasycarpum). Yery common. 



Eriophyes acericola. The mature galls are green and resemble in form 

 and position the summer cases of the cigar-case-bearer. The interior wall 

 is granular and parallel excrescences are found, but even at maturity they 

 do not extend to the centre of the interior as in the case of E. quadripes. 

 Occurs on Hard Maple (Acer saccharnvi). Yery common. 



Eriophyes ahnormis. Produces balloon-shaped galls on the upper sur- 

 face of the leaf. The apex of the gall is usually serrated. The interior has 

 ridges projecting inward and the folds in the old galls nearly fill the cavity. 

 Occurs on Basswood (Tilia Americana). Yery common. 



Eriophyes ulmi. The galls are intermediate in form between those of 

 the Hard and Soft Maples and somewhat balloon-shaped. The interior wall 

 is ridged vertically. The galls usually occur on the upper side of the leaves. 

 Occurs on vSoft Elm (Ulmus Americana) and Rock Elm (Ulmus RaceTnosa). 

 YeTj common. 



Eriophyes sp. Produces irregular wart-like swellings on the upper sur- 

 face of the leaves of the Manitoba Maple. The swellings are green at first 

 but turn s^ray when mature. The average diameter of the gall is about 

 3 m.m. The under surface of the galls appears as irregular concavities lined 

 with a granular secretion, which is greenish at first and rusty brown when 

 old. Occurs on Manitoba Maple (Acer negundo). Common. 



Eriophyes phloecoptes. Produce tubercular gall masses which encircle 

 the base of the buds and shoots of the cultivate^ plum. The galls are about 

 one-sixteenth of an inch in diameter, and the interior is granular with a small 

 cavity in the centre. As many as sixty-two of these mites were found in 

 a sinsrle gall. Occurs on cultivated Plum (Prunus domestica). Not common. 



Eiiophyes sp. This species produces an abnormal cjTOwth of the buds 

 of the Yellow Birch. The terminal growth of the twig is checked and large 

 bunches of buds are formed sometimes as large as a hen's egg. The galls 

 remain on the tree, <?ivinor ^he tree an unsightly appearance in winter. Oc- 

 curs on Yellow Birch (Betula lutea.) Common. 



