HISTORY AND PHYSIOLOSY. 47 



half an hour, with the unmistakable marks of her 

 amours upon her. Excursions are sometimes made 

 for a shorter period, but she seldom exhibits signs of 

 being impregnated after these.. 



According to Huber, ope impregnation is sufficient 

 to fertilize all the eggs that are laid for two years 

 afterward, and perhaps sufficient to fertilize all that 

 she lays during her whole life. This may seem in- 

 credible to many; but need not, when we consider 

 that in the common spider, according to Audibert, 

 the fertilizing effects continue for many years. 



Impregnation in insects appears to take place 

 whilst the eggs pass a reservoir containing sperm, 

 situated near the termination of the oviduct in the 

 valve., "In dissetfting the female parts in the silk 

 moth," says Mr. Hunter, "I discovered a bag lying 

 in what may be called the vagina or common oviduct, 

 whose mouth or opening was external, but it had a 

 canal of communication between it and the oviduct. 

 In dissecting these parts before copulation, I found 

 this bag empty; and when I dissected them after- 

 ward, I found it full," By the most decisive ex- 

 periments, such as covering the ova of the unimpreg- 

 nated moth after exclusion, with the liquor taken 

 from this bag, found in those which were known to 

 have had sexual connection, rendering them fertile, 

 he demonstrated that this bag was a reservoir for the 

 spermatic fluid, to impregnate the eggs as they were 

 ready for exclusion, and that coition and impreg- 

 nation were not simultaneous. 



Linnaeus thought there was a sexual intercourse 



