December, '08] JOURNAL OP ECONOMIC ENTOMOLOGY 355 



fulaia, leaving only 49 larva, or 10 per cent of the whole number, 

 nninfested; yet 61 larvae were able to pupate. From these 61 pupas, 

 however, only 7 adult moths emerged, showing a total mortality among 

 the Army AVorm from larva to adult of 98.6 per cent. And since 90 

 per cent of the larva? were infested with the eggs of this parasite, it 

 would seem to indicate that, in this case at least, the parasitic fly was 

 decidedly the most important factor in causing the high mortality of 

 the Army Worm. In a few cases it was found that where only a 

 single parasitic egg was attached to a larva, that the host Avas able to 

 complete its transformations. 



The greatest number of parasitic eggs observed on a single larva 

 was 12, with an average of 8 for the entire number (1:4:2) infested. 

 The 442 infested larva yielded 709 parasitic puparia, or an average 

 of nearly two for each infested larva. The 709 pwparia yielded 556 

 adult parasites. The greatest number of adult flies from a single 

 Army Worm was four. These figures show that the mortality with 

 the parasitic fly from egg to puparium was 52 per cent, and from 

 puparium to adult 22 per cent, making a total mortality from egg to 

 adult of 73 per cent. 



This shows that the tendenc}^ would be for the fly to continually 

 gain in relative numbers, owing to the lighter mortality, and easily 

 accounts for the complete subjugation of the Army Worm in normal 

 years by this one natural enemy. No other parasites were found in 

 the course of these experiments. 



NOTES ON THE HEN FLEA (XESTOPSYLLA GALLIN- 



ACEA) 



By Glkxn W. Herrick 



During the summer of 1907 the ground beneath one of the dwelling 

 houses on the campus of the Mississippi Agricultural College be- 

 came infested with fleas to such an extent that the occupants were 

 greatly annoyed by these pests. On examination I found that two 

 species were present beneath the house, namely, the hen flea and the 

 dog flea. The house, of course, stood on brick pillars some distance 

 above the ground, and thus gave opportunity for hens to go under, 

 where they would lay eggs and rear chickens. Dogs and cats also had 

 free access to the space beneath the house. To secure relief the space 

 under the house was treated with a thorough dusting of slacked lime 

 and nothing more was heard from the occupants until the summer of 

 1908, when the fleas again became troublesome. 



