• REPORT^OF THE z ENTOMOLOGIST. 125 



of gutters, from the eaves of houses. Here they swarm in the form of 

 young tadpoles or bull-heads, and our rain-water casks, unless tightly 

 covered, serve as nurseries or breeding-places for the million of mosqui- 

 toes which annoy us so much in the evening and during the night. A sin- 

 gle bucket or pitcher of rain-water carelessly left for a few days in a 

 bedroom, will serve as a convenient and commodious breeding-pond for 

 some thousands of mosquitoes. A little sweet oil poured on the water 

 in a cask or reservoir will destroy these larvie, as they have to come to 

 the surface for the purpose of breathing, the oil closing up their organs 

 of respiration. If the water be drawn from below the oil, by means of 

 a siphon or spigot, the oil will still remain on the surface and not become 

 mixed with the water so as to injure it for the purpose of washing, &c.; 

 at the same time it is somewhat questionable if the water will not lose 

 some of its good qualities for drinking purposes by being completely 

 cut oft' from the action of the air. The larva? of mosquitoes are said to 

 be of some utility as forming food for young fishes, and as destroying 

 minute confervce, and other substances which would otherwise generate 

 in the water, and, by their decay, render it putrid and offensive. When 

 "camping out " in the woods, a "smolder" of smoke from damp wood 

 and leaves to windward will drive the insects away. Citron or lemon 

 juice, ammonia or ether, and camphor, will allay the irritation caused by 

 their bites, and burning camphor in a room is said to drive the insects 

 away ; and when unprotected by veils or mosquito-nets, a little of the 

 oil of pennyroyal rubbed over the hands and face has been found useful 

 in banishing them, and a sponge saturated with it, hung at the head of 

 the bed, over the face of the sleeper, when unprotected by anything else, 

 is said to be effectual in driving them off, as they endeavor to avoid this 

 scent, which appears to be very offensive to them. Dilute carbolic acid 

 and coal-oil or kerosene have been used in the same manner, but ife is 

 somewhat doubtful whether the smell of the coal-oil is not more offen- 

 sive even than the bite of the mosquito to most persons, and in that 

 case "the remedy" would be almost " worse than the disease." 



The eggs of the Hessian fly {Cecidomyia destructor) (Fig. 10) are de- 

 posited in longitudinal creases in the blade of the plant of wheat, bar- 

 Fig. 10. ley, rye, &c., in autumn and spring. 

 These eggs hatch in from four to 

 twenty days, according to the state 

 of the weather. The larva? or grubs 

 crawl down, working their way be- 

 tween the leaf and main stalk till 

 they come to a joint, where they re- 

 main and suck the sap. They attain 

 their full growth in from four to six 

 weeks. The pupa is formed in the 

 same place, its outer covering or j)u- 

 parium resembling a flax-seed. The 

 winged insects appear in April and 

 May, and lay their eggs in wheat 

 and other cereals. Curtis says that 

 I'eeding the wheat off with sheep in winter might possibly save the crop 

 from the Hessian fly. Dr. Harris recommends the same as a partial 

 remedy. Mr. Herrick states that the stouter varieties of wheat should 

 be chosen, and the land kept in good condition. If fall wheat is sown 

 late some eggs will be avoided, but the risk of winter-killing will bo in- 

 curred. Great numbers of the pupae may be destroyed by burning the 

 stubble immediately after harvest, and then plowing and harrowing; the 



