390 



NEW YORK STATE MUSEUM 



association with other insect attack; some species are met with in cow- 

 dung (Theobald). 



A Notable Species of Sciara. 



A species (perhaps more than one) is noted in Europe, for its gre- 

 garious and migratory habits. It is there known as the army-worm or 

 Heerwurm from its collecting at certain seasons in companies — some- 

 times consisting of millions — and traveling along in a body of often from 

 twelve to fifteen feet in length and two or three inches broad and perhaps 

 a half inch thick. " M. Guerin Meneville observed columns as many 

 as thirty yards in length." The species has not been positively deter- 

 mined, but it is accepted as either Sciara Thomoe (Linn.) or S. mili- 

 taris Now. — but probably the latter, according to the statement of 

 Baron Osten Sacken. Similar gatherings have been observed in this 

 country, one of which is narrated in Insect life, iv, 1891, page 214; 

 two others recorded by Glover in the Report of the Commissioner of 

 Agriculture for 1872, p. 115, as observed in Virginia (figures of the 

 larva and fly are given) ; and two others by Prof. F. M. Webster, in 

 Science for Feb. 23, 1894, p. 109. With us they bear the name of 

 " snake-worms," from the snake like appearance and movements of 

 some of the processions. 



Those who have access to Figuier's Insect World may find therein 

 (pages 46, 47) some interesting details, taken from the writings of M. 

 Guerin-Meneville, respecting migrations of these larvae observed on 

 the borders of forests in Norway and Hanover, and their conduct upon 

 meeting obstacles, when their ranks are broken, and when the two ends 

 have been brought together; also, some strange superstitions respect- 

 ing them, entertained by the peasants of Norway and Siberia. No sat- 

 isfactory explanation has yet been given for the assemblage of such 

 myriads of these footless larvre and their marches in the brightest 

 sunlight. 



The Yellow-Fever Fly. 

 Another species of Sciara has been named in its winged state, " the 

 yellow-fever fly," from its appearance in immense number (in 

 swarms) on different occasions in some of the Southern States, during 

 the prevalence of the epidemic from which it has drawn its name. As 

 appears from an article by Dr. Hagen, in Psyche, iii, 1880, p. Ill, 

 entitled "The Yellow-fever Fly," no literature relating to these 

 appearances could be found. They rested only on report. From a 

 specimen collected in New Orleans ia 1848, and marked as "the yel- 

 low-fever fly," which came to the Cambridge Museum, Dr. Hagen 



