404 



NEW YORK STATE MTJSEtH 



years and in some localities they are conspicuously more numerous than 

 in others. In gathering a quart of field mushrooms several specimens 

 may be entirely free from any sign of attack, and in others only a few 

 newly -hatched larvae are at work. Then, again, one may meet with 

 particularly large mushrooms a day or two past their prime which are 

 tunneled like a sponge and are living masses of maggots." 



Remedies. 



In consideration of the fruitless and long-continued efforts made by 

 mushroom-growers to find an antidote against this insect, and a seem- 

 ing general conviction that the culture must cease at the advent of 

 warm weather, it may not be worth while to make suggestions for 

 further experimentation. Still, much would be gained if the period of 

 culture could be extended by a month or two. If an insecticide is to 

 be sought, it might naturally be looked for among the vegetable ones . 

 Of these, pyrethrum is certainly one of the most efficient, and the 

 Diptera are known to be particularly sensitive to its influence. The 

 pure, fresh, dry powder blown in the atmosphere with a powder- 

 bellows, or made up into slightly dampened cones for slow burning, 

 would unquestionably kill nearly all, if not all, of the ever-active, 

 leaping and running flies in the apartmeLt. If their eggs have not 

 been previously deposited, their further propagation would be pre- 

 vented. There seems no reason why a newly-made solution of the 

 powder (largely soluble in water), liberally sprinkled over the soil, 

 should fail to kill the young larvae at the moderate depth in the bed 

 at which they occur before entering into the base of the stalk, and at 

 the same time be harmless to the plants. 



Some Literature of Phora 



Latreille: Hist. Nat. des Crust. -Ins., xii, 1804 (genus founded). 



Macquart: Hist. Nat. Ins.— Dipt., ii, 1835, pp. 625-631, pi. 24, figs. 1-4 (30 



French species characterized). 

 Westwood: Introduc. Classif. Ins., ii, 1840, pp. 574, 575 (habits), f. 132, 12, 13 



(larva and imago). 



Loew: Mon. Dipt. N. Amer., Pt. I, 1862, p. 4 (antennal structure), p. 47 

 (family characters). 



Packard: in Amer. Nat., ii, 1868, pp. 196, 197, pi. 4, figs. 1, 2, 3 (P. incrassata 

 parasitic in larva of honey-bee in England); the same, in Cotton 

 Insects, 1879, p. 209; Guide Stud. Ins., 1869, p. 127 (parasite of hive- 

 bee), p. 416 (figures of P. incrassata as cause of "foul brood"); the 

 same, in Entomol. Begin., 1888, p. 126, f. 146; in Amer. Nat., v, 1871, 

 p. 745, f. 123 (of cave Phora). 



Scudd.-Burg.: in Proc. Bost. Soc. Nat. Hist., xiii, 1870, p. 283, f. 17 of plate 

 (asymmetrical genitalia of P. microcephala). 



