Insects. ©753 



third discoidal cell, which is black. Fig. 10 represents the female 

 magnified. 



The male differs in being smaller and more attenuated, also in the 

 shape of the antennae and of the last abdominal segment, added to 

 which the anterior and intermediate coxae are generally entirely 

 shining black. In order to show the difference in the appearance of 

 the abdomen in the two sexes, 1 have figured the terminal segments of 

 both. Fig. 13 represents that of the male ; a appeared to me to be the 

 penis ; e the head of one of the two little black processes, which are also 

 found in the female : fig. 14 is the female abdomen, in which b repre- 

 sents the saw, curving outwards and downwards between the terminal 

 valves : lastly, at fig. 15, are the saw and ovipositor. The superior 

 portion, which is somewhat serrated at the apex, represents the left 

 half of the ovipositor and the inferior portion the left valve of the save. 

 This is armed at the under side with a number of angular and square 

 teeth, and at the sides with rows of exceedingly sharp points. 



From what has been stated, it may be concluded that this species 

 produces but one or at most two generations in the year. I found, 

 however, that, taking individual cases, the progress of the metamor- 

 phosis was very unequal : thus Dr. VVttewaall informs me that from a 

 number of larvae, which he collected and took home on the 4th of July, 

 18o7, some imagos made their appearance on the 25th of July, making 

 an interval of twenty-one days, and that others did not develope till 

 the 29lh of May of the following year. It is difficult to suggest a 

 cause for this difference, as the conditions and circumstances were the 

 same for the whole number of larvae. 



I will now note in how far other authors differ in their accounts 

 from what I have slated as the result of my own observations. 



From various points in Goedaert's twenty-eighth description, con- 

 tained in his first volume, I conclude that he had this insect in view; 

 but more particularly from the fact that he represents the antennae of 

 the imago as somewhat clavate. The life-history agrees very well (his 

 insects also remained ten months in the cocoon), but the figure of the 

 larva, otherwise tolerably good, shows only sixteen legs, instead of 

 eighteen. 



Rosel informs us that he met with this species on willows and 

 gooseberry-bushes; I take the liberty of doubting the correctness of 

 this, and conclude that he must have taken some species of Nematus 

 for our present insect, there being members of that genus strongly 

 resembling Hyloloma Rosae. He does not say that he reared the 

 larvae found on willow and gooseberry, but only that he observed 

 VOL. XXIII. 3 B 



