INSECTS INJURIOUS TO THE LOCO WEEDS. 



39 



larval stage it displays a rcinai'kahlt' diversity of habits, althouirh it 

 IS evidently by choice a root feeder and is also, with the seed-corn 

 maggot and many related insects, a scavenger by nature, following in 

 ^ome cases original attack by some other form of insect. It has been 

 recorded by Dr. L. O. Howard as having been bred from larva^ in 

 human excrement in houses and out of doors. Mr. E. (r. Titus has 

 reared it from sugar beet collected at Ohiey, Colo., and from cockle- 

 bur collected at St. ^latthews. S. C'.. where it was feeding in the cells, 

 of a Aveevil, II (iris fraiiscirxa. In September, lOO."). it was reared by 

 the writer from onions infested by Tritoxa fea-a from Williamson 

 School, Pa., and there is positive evidence that it had fed on the 

 onion bulbs, as neither stems nor leaves Avere present. Dr. J. B. 

 Smith also has reared it from onions. In 10()(» it was reared from 

 corn on the farm of Dr. B. T. (ialioway near the District of Colum- 

 l)ia, where it was reported injurious, the injury being at first attrib- 



FiG. 11'. — Spotted root fly iEiu-tsId uotatai : Adult male at right; fcniali' at left. 

 Miu-h cnlarsed (original I. 



uted to the seed-corn maggot, as attack was to seed corn and resem- 

 bled the work of the latter species. From cabbage it has been reared 

 on two occasions, viz. from the roots collected at "Washington. D. 

 C, and from maggot -infested roots received from Bethel, Alaska. 

 It has also been bred from the pulp of Osage orange, from apples in- 

 fested by the codling moth, from sumach fruit, from the bolls of 

 cotton, and from Sohmum. It is not rare in diseased cotton bolls. 



This fly belongs to the same family as the preceding, the Ortali- 

 da>, and is shown in figure 12. where it will be seen that it has a large 

 head and flat bo(h\ Each wing is marked with two black spots. 

 The female is distinguished from the male by its more slender form, 

 smaller head, and pointed abdomen, which bears near the anal ex- 

 tremity a distinct wiiite ti-ansverse band. The body is metallic blue. 



Our rearings show that larvie have come under observation from 

 May 27 to as late as October 2 and that flies ha\e issued fi-oni various 

 sources June 10-July 80, September >i-21, and throughout October. 



