232 Forty-fourth Report on the State Museum 



pipe (logs), a portion of which had been there for from fifty to 

 seventy years. The water stood in it usually at a depth of two feet. 

 At the bottom was a sediment of light mud covered over with 

 confervae which also grew upon and around the sides of the tank, in 

 all stages of growth and decay. Of the " rat-tails " — some were 

 swimming about in the water at the depth of a foot or more below 

 the surface; some were creeping slowly, or more often remaining 

 quiet on the sides of the tank, also below the surface; others (per- 

 haps a fifth part or less) were floating along with expanded end of 

 tail at the surface, but a sudden jar would at once send them down- 

 ward. They weie able to remain underneath without coming up for 

 respiration for a much longer time than the larval mosquito. They 

 were very sluggish in all their movements. Of those resting on the 

 sides of the tank, some were at just the height to reach the surface 

 with the tip of their tails. A few were observed on the outside of 

 the tub, on the shady or moist side, apparently working their way to 

 the ground, where they burrowed into the soft, wet soil, and into 

 some decaying portions of a willow log. It did not appear that any 

 buried into the mud at the bottom of the tub, although it was an 

 inch or more in depth; indeed they were seldom seen on the bottom 

 except as they might be hanging downward from the side. It 

 seemed to me, although I could not determine the fact, that the larvae 

 were feeding on the decaying confervas in the water. The tub was 

 partially overhung and shaded for most of the day by a willow tree 

 standing on the opposite side of the highway. 



I endeavored to procure more of the larvae for you in 1886, but 

 they did not make their appearance. The year following my father 

 removed the water-tank in consequence of a diminished water supply 

 from the old pipes, and since then, although I have kept them in 

 mind at their usual time of coming, I have not been able to find them 

 elsewhere. 



Erroneous Larval Habits Reported. 



In the American Entomologist, ii, 1870, pp. 141, 142, Mrs. Mary Treat 

 in a paper entitled "Plant-lice and their Enemies," has given an 

 account of the habit of some Syrphus-fly larvae which she had reared, 

 as minutely detailed, from eggs deposited by the parent flies among 

 some plant-lice infesting Chrysanthemum slips while under glass. In 

 an extended note upon the article, appended by the editor, C. V. 

 Riley, he remarks as follows: " At our request Mrs. Treat has sent us 

 some of the bred flies mentioned in this article, and among them are 

 three species of the genus Syrphus, and one of Helophilus. The lat- 

 ter is the H. latifrons of Loew (Fig. 94)." The species, 

 was evidently correctly identified and illustrated by 

 Professor Riley (it is given in Fig. 5 from an electi'o- 

 type furnished) but there is clearly some mistake in 

 the matter. Helophilus latifrons could not have been 

 Fig. 5.— Helophi- reared from larvae feeding on plant-lice. Its larva is 



LUS LATIFBONS, . in. ^ ^ /-t- • ,1 



natural size. aquatic only, and wholly incapable of nving m the 

 manner stated. Some error probably occurred in the 

 examples sent by Mrs. Treat. 



