18 JOURNAL OP ECONOMIC ENTOMOLOGY [Vol. 1 



Herrera is doing in Mexico and referred to some of the difficult prob- 

 lems which he encounters. 



Mr. Felt presented a paper as follows: 



OBSERVATIONS ON THE BIOLOGY AND FOOD HABITS 



OF THE CECIDOMYIIDAE 



By E. P. Felt, Albany. N. Y. 



The species belonging to this family, though small and easily dis- 

 tinguished from most other Diptera, are exceedingly abundant and 

 subsist in the larval stage under quite varied conditions. The ma- 

 jority of forms live upon plants and a goodly proportion produce 

 galls. These peculiar structures occur upon the roots, root stalks or 

 underground buds, along the stem, on the branches, on the leaves or 

 even among the flowers or flower heads as the case may be. One 

 genus for example, Rhopalomyia, attacks all parts of various Soli- 

 dagos, except perhaps the root, the galls being quite varied in character 

 and the adults from the same representing distinct species and, so far 

 as known to us, coming only from galls possessing certain characters. 

 On the other hand, Asphondylia monacha 0. S., a most striking form, 

 occurs not only in terminal rosette galls on the narrow-leaved Solidago, 

 Euthamia lanceolata and E. graminifolia, but may breed in apparently 

 unaffected florets of the same plant or may be found in what we have 

 designated as adherent galls on Solidago canadensis and S. serotina. 

 These latter structures are inhabited by two species belonging to as 

 many genera and appear to be produced by the female laying eggs 

 between the closely apposed young leaves in the rapidly growing bud. 

 The larvae cause a depression on each surface and the margins adhere, 

 so that when the plant develops and the leaves turn down, the pair 

 affected adhere at the point of injury though their bases are an inch 

 or more apart. The form of the gall appears to be determined largely 

 by the location and number of eggs the female deposits ; for example, 

 the midrib deformity on ash leaves, known as the gall of Cecidomyia 

 pellex, may range in length from about 1/2 to 214 inches. It appears 

 to develop directly as a result of the larval irritation on the upper 

 surface of the midrib; the size of the gall being proportionate to the 

 number of larvae, small ones having perhaps five or six, while the 

 largest may have as many as 50 to 60. Certain species breed in more 

 or less regularly rolled leaves, and in this case there seems to be a 

 comparatively slight irritation and the form of the roll is governed 

 mostly by the location of the larvae and the structure of the leaf. 

 Other species subsist in more or less irregular depressions, and here 

 again the irritation is comparatively slight. There is one form, for 

 example, which produces a slightly depressed rectangular area on the 



