46 Notes on the Distribution of Insects^ Sfc. 



places Pyrophorus noctiliciis, a West Indian insect, in the Ameri- 

 can fauna. The authors of " Melcheimer's Catalogue " reject it 

 for want of proof as to its naturalization, probably attributing 

 its introduction to accident. If Mr. H. really captured a living 

 specimen in the U. States, his authority is quite sufficient. 



A distribution of insects is also effected by means of import- 

 ino- cattle from one country to another. By this means, a few- 

 species of the Dipterous order of insects have been introduced 

 into this country ; one of these is the (Estrus ovis. Our sheep 

 owners may be ignorant of the fact that this insect parasite is 

 prolific in Canada, being a pest to sheep in winter as well as 

 summer. Entomologists, by strict attention to the habits of this 

 fly, have discovered the manner in which the species is propa- 

 gated in the nostrils of the sheep. While the animal is grazing, 

 the female fly watches an opportunity to alight on its nostrils 

 deposit its eggs, which are placed in the frontal sinus, in the 

 midst of the mucus which they contain. Each larva is provided 

 with a pair of hooks to assist it in motion, and with which it 

 inflicts wounds, and then feeds upon the matter generated therein. 

 When the larvce are full grown, they fall through the nostrils 

 and chano-e to pupw on the surface of the earth. In March, 

 1856, five of the Im^rce of this fly were taken from a sheep's head, 

 obtained from the Toronto market. The party who purchased the 

 head, did not know how "the worms," as he called them, got 

 there, and made no use of it, being under the impression that 

 the animal had died from disease. Sometimes the irritation pro- 

 duced by the larvce is so excruciating that the animal runs about 

 continually, rubbing its nose on the ground, and it frequently 

 loses the power of its feet. There have been several instances in 

 Eno-land which proved fatal. The disease is called " Staggers " 

 by persons who are ignorant of the cause. The larvce can be des- 

 ■ troyed by injecting tobacco juice into the nostrils. 



It is indeed probable that the Dipterous wheat parasite 

 which is now propagating to an alarming extent in this coun- 

 try and where it has done so much damage to the staff' of 

 life mav be traced to some European country in which it is at- 

 tached to another species of cereal, and that naturalists take 

 no more notice of it than that it does exist. Many species of all 

 the orders of insects, v/hile in the larva state, derive nourishment 

 from more than a single vegetable substance ; and any person 

 who has studied Insect life, can see that every paj-ent insect is 



