ENTOMOPHTHOREAE OF THE UNITED STATES. 173 



proportions. It was first reported from this country by Mr. J. C. Arthur who describes 

 iisiS, Entomophthora JPhytonomi n. s., having found it destroying the clover weevil (Phy- 

 tonomus punctatus) in great numbers in the vicinity of Geneva, ]S^. Y. The affected 

 larvae, just before death, crawl np blades of grass, etc., and curling themselves around 

 them near the summit are attached by the rhizoids in this position. Material of the 

 Phytonomus form received by me from Professor Riley, which was collected, I believe, 

 by Professor Lintner at Albany, I^. Y., shows no sufficient differences which can sepa- 

 rate it from the same form on other hosts, although the average measurements of the 

 conidia are very slightly larger than in the majority of cases, the maximum length given 

 by Arthur being 28,«, while as a rule I have seldom found it more than 25,a. The shape 

 of the spores is identical with that which characterizes the other forms and is similar to 

 the published figures of E. sphaerosperma to which all the forms occurring on the hosts 

 above enumerated should, I feel confident, be referred. 



In my own experience, I have observed two epidemics caused by this species: one 

 among certain small flies in a wood near marshy ground at Kitteiy, Me., where the 

 hosts occurred in considerable numbers fixed by the fungus on the under side of the 

 lower leaves, a few feet from the ground. The second instance occurred in two orchards 

 in the same locality where the hu.ndreds of the previously mentioned epidemic were re- 

 placed by tens of thousands, the host in this instance being the leaf-hopper {^TypTilocyha 

 mali and rosae), a pest only too well known to cultivators of roses. Having first ob- 

 served it in some abundance on roses in a garden, I was led to make an examination of 

 adjacent apple orchards, and found the lower branches of the trees literally covered with 

 the affected hosts, a dozen or more being often fastened to a single leaf. Unfortunately, 

 I was too late, and in almost all cases the specimens had discharged their spores, while 

 no more hosts remained for infection. A few, however, were still producing conidia, 

 and it occurred to me to endeavor to infect from them the larvae of Pieris, which is the 

 common European host of this species. For this purpose I placed a small number of 

 young larvae in the bottom of a jelly tumbler, fixing the infected hosts above them as 

 previously described. This was on Sept. 10 (1886) ; on Sept. 16, the majority had pre- 

 pared to pupate, the larvae having been too far advanced when infected. One larva, how- 

 ever, on the evening of the sixteenth, was found dead and attached to the leaf on which 

 it had been feeding by powerful rhizoids which issued from the region of the prolegs. 

 This larva was not disturbed for twenty-four hours, in the hope that conidiophores might 

 make their appearance, but none appeared, and the insect became slightly collapsed. 

 Upon examination, it was found to contain numerous, spherical resting spores, about 25,(t 

 in diameter, the origin of which could not be seen, all traces of hyphae having disap- 

 peared owing to a partial decomposition of the contents of the caterpillar which also 

 contained several larvae of Pteromalus. This fact surprised me greatly, since, in his 

 infection experiments, Brefeld states that no result was produced when spores were sown 

 on larvae thus infested. A double parasitism was also found in my experiments with 

 E. Orylli previously mentioned, in which the larvae of certain insect parasites issued 

 from several caterpillars thickly covered by conidiophores. The remaining larvae in the 

 present experiment died with Pteromalus or pupated within a day or so. Several died 

 from Pteromalus after pupation, and the remainder, three or four in mimber, died before 



MEMOIRS BOSTON SOC. NAT. HIST., VOL. IV. 25 



