128 CLASS INSFXTA. 



mon iulus commences towards the end of December, and 

 finishes towards the middle of May. The copulative organs 

 of the male are placed, in this species, under the sixth seg- 

 ment, but they are not apparent, as genital parts, until the 

 individual has attained about a third of its ordinary size. 

 Until then, this place is occupied by a pair of feet, the 

 fifteenth, and which always exists in the females. In them, 

 the orifice of the sexual parts, is placed between the first and 

 second segment. In certain glomeris and female iuli, I have 

 observed behind the origin of the second pair of feet, two 

 small convex nipples, which appear to characterize the sex. 

 That of the males also consists of two nipples, but each ter- 

 minated by a scaly crochet. In copulation, these insects are 

 upright, and apply face to face, the anterior extremities of 

 the body, entwining below. The body of individuals just 

 born, is kidney-formed, perfectly smooth, and without appen- 

 dages. Eighteen days after, it undergoes a first moulting, 

 and they then assume the form of the adults. But, still, 

 they have only twenty-two segments, and the total number 

 of their feet is twenty-six pairs. M. Savi appears to contra- 

 dict the assertion of De Geer, who says that he counted but 

 three pairs, and eight rings in the young individuals. But 

 is it very certain the moulting of which M. Savi speaks is 

 really the first ? and should we not, on the contrary, presume 

 that these young individuals do not pass suddenly from a 

 state in which they exhibit no locomotive appendage, to that 

 in which they have twenty-six pairs of feet ? or that, in a 

 word, some other changes of the skin, but which may have 

 escaped M. Savi, have taken place, and have successively 

 developed this number of feet ^ Do not the observations of 

 Reaumur, the Swedish naturalist, confirm these gradual 

 transitions ? Be this, however, as it may, according to M. 

 Savi, the first eighteen pairs of feet only serve for locomo- 

 tion. At the second moulting, the animal has thirty-six 



