348 

 Drosophila dimidiata Loew 



Drosophila dimidiata Loew, Berl. Ent. Zeitschr., 1862, p. 230. 



Piiparium. — Leni^th, 2 mm. Pale reddish yellow, slightly shining. 

 General habitus similar to that of Drosophila adiista. Anterior respira- 

 tory organs about three times as long as their diameter, terminating in 

 numerous fine hairs (PI. LXXXIV, Fig. 5). Surface of abdomen 

 with the usual transverse bands of short setulse ; apex of abdomen with 

 a scalelike projection as shown in Figures 6 and 7, Plate LXXXIV; 

 above the base of the apical pair of respiratory processes is a pair of 

 small tubercles; cephalad of the scalelike process the surface of the ab- 

 domen is broken by 2 or 3 narrow but deep depressions. 



The exuvia from which the above description was drawn are those 

 of adults reared from larv?e obtained by Mr. Hart and the writer at 

 Havana, 111., November 16, 191 3. The larvaj were found feeding in 

 fungus on the trunk of a fallen decaying tree on the bank of the Illi- 

 nois River. The imagines emerged November 21, 191 3. 



This species was originally described from imagines obtained in 

 Illinois by Le Baron. Aldrich in his "Catalogue of North American 

 Diptera", 1905, gives only the original locality. It is one of the com- 

 monest species at Urbana, occurring on windows in the Natural His- 

 tory Building, and on fungi on the campus of the University during 

 the summer. Professor Aldrich informs me that he has taken the 

 species at Lafayette, Ind. 



AGROMYZID^ 



The larval habits of the species contained in the genus Agromyi^a 

 are similar in that all those known are phytophagous, but they differ 

 in the point of attack which they select, some mining in leaves, and 

 others in the roots or in the stem. All so far reported are internal 

 feeders, and several are of economic importance, two of the latter class 

 recently discovered being Agromyza pruinosa Coquillett — mining the 

 cambium layer of birch — and A. pruni Grossenbacher, mining the cam- 

 bium of Primus. The last-named species I describe in the present 

 paper. It has not been taken in this state, but almost certainly occurs 

 here. As the original description is very brief and not readily acces- 

 sible to entomologists I take the opportunity of re-describing it from 

 material kindly supplied me by Mr. Grossenbacher, who reared the 

 species. 



There are a large number of very closely allied species in the genus 

 Agromyza, and much careful work upon the early stages and food 

 habits is necessary before we shall be able to decide just how many dis- 



