352 



sions and on the posterior 3 segments. Surface with similar processes 

 to those of the larva, but almost indistinguishable because of the 

 ground-color. Prothoracic respiratory organs very small. Depressions 

 on body very deep, those on dorsum very conspicuous, slightly cres- 

 centic in shape. Apex of abdomen similar to that of larva except that 

 in hardening the projecting portions are contracted considerably and 

 are less clearly distinguishable. 



Reared from leaves of Sctaria glaiica, the larvae occurring in the 

 apical 6 inches of the leaf, usually 4 or more in each mine. In com- 

 pany with another species angulata was found to be present on vacant 

 lots both in Urbana and Champaign in July and August, 191 5, their 

 work showing up readily because of the conspicuous whitening of the 

 tips of the affected leaves. Angulata has previously been recorded as 

 attacking timothy grass*, and it will also feed on wheat. A summary 

 of investigations of the habits and life history of this species, with 

 figures of the imago and puparium, are given by Webster and Parks. f 



Descriptions of New Illinois Diptera 



In the course of the year it frequently happens that specimens are 

 taken in general collections, or in connection with other work, which 

 belong to undescribed species. Often these species are of economic 

 importance, and usually they are small forms which are readily over- 

 looked in the field. It is considered necessary in the interests of 

 students of the represented order to place the occurrence of such species 

 upon record ; to give adequate descriptions of them ; and to indicate 

 their relationships with already described species. Isolated descriptions 

 of new species unless very full are often useless for the purpose of 

 identification because of their inadequate nature or the omission of 

 the essential characters by means of which the species of the genus are 

 separated. Many species have been described by writers who were 

 unacquainted with congeneric species, and because of tliis ignorance 

 they either did not compare their so-called new species with those 

 already descril)ed, or they compared it with some species to which it 

 bore but a faint resemblance. The present writer in all cases compares 

 the new species he describes with the forms most closely related, not 

 because he presumes to set an example but because he considers it his 

 duty to do so. 



*M,all()(-h. — A Revision of the species in Agromyza Fallen, and Cerodontha Eon- 

 dani, Ann. Ent. See. Amer., Vol. 6, No. 3, 1913, p. 304. 



tThe Serpentine Leaf-miner, Jour. Agr. Research, Vol. 1, No. 1, Oct. 10, 1013, 

 pp. 83-84. 



