Packard.] 148 [Nov. 19, 



broad lateral golden gray band interrupted by the sutures. The base 

 of the first abdominal segment has a yellowish band, interrupted in 

 the middle. On the middle of the end of the two succeeding seg_ 

 ments is a triangular mesial golden spot, with an oblique irregular 

 band on each side, and farther down the sides golden ; terminal seg- 

 ment golden. Base of wings, scales and halteres yellowish-white. 

 Legs black. 



The male differs from the female in the front between the eyes be- 

 ing about one-third as wide as in the latter, while she is rather the 

 smaller. Length .22-32 inch. 



The species agrees in most particulars with Harris' description of 

 Musca harpyia in his " Correspondence/' and we are inclined to 

 think that individuals of this species formed the subject of his de- 

 scription. After comparing it with about a dozen specimens of Musca 

 domestica received from Switzerland (through the kindness of Mr. S. 

 H. Scudder), we cannot find that it differs in any respect from them. 

 The golden color that Harris calls silvery, the reddish oval spot on 

 the vertex, the black hairs on the thorax, are the same in specimens 

 from America and Switzerland. Both also agree in the venation 

 and form of the head and front. 



SUMMARY OF ITS HISTORY. 



The eggs are laid about one hundred and twenty in number, and 

 in twenty-four hours the larva? are hatched. 



There are three stages of the larval state, and consequently two 

 moults. 



The first stage lasts about one day (twenty-four hours). 



The second stage lasts about one day. 



The third stage lasts three or four days. 



The entire larval state averages from five to seven days. 



The pupal state lasts from five to seven days. 



The period from the time of hatching to the exclusion of the im- 

 ago lasts from ten to fourteen days in the month of August. 



Those larvae which were reared in too dry manure were nearly one- 

 half smaller than those taken from the manure heap. For several 

 days the larva? living in this dry manure did not grow sensibly. 

 Too direct warmth, but more especially the want of moisture, and 



