266 STATES OF INSECTS. 



month in the third year a . Mr. Jones of Chelsea, a most 

 acute lepidopterist, in one of his excursions captured a 

 female of Arctia mendica, another moth, which laid a 

 number of eggs, thirty-six of which produced caterpil- 

 lars : all these fed, spun their cocoons, and went into the 

 pupa state in the usual manner, but at the proper season 

 only twelve produced the fly. As this was no uncommon 

 circumstance, he concluded that the rest were dead : to 

 his great astonishment, however, in the next season twelve 

 more made their appearance ; and the following year the 

 remainder burst into life, equally perfect with the fore- 

 going b . In this extraordinary result, which also occa- 

 sionally has been observed to take place in the emperor- 

 moth (Saturnia pavonia), the privet-hawkmoth {Sphinx 

 Ligustri), and that of the spurge (S. Euphorbia:) c , and 

 other species, — it is clear that something besides mere size 

 and temperature is concerned : for, these circumstances 

 being precisely alike, one pupa arrives at maturity in six 

 months, and another of the same brood requires between 

 two and three years. We can guess, that the end which 

 the All-wise Creator has in view, in causing this remark- 

 able difference, is the prevention of all possibility of the 

 destruction of the species. Eriogaster lanestris and Arc- 

 tia mendica, &c, for instance, are doomed, for some rea- 



a Haworth Lcpidopt. Britann. i. 125, An instance is recorded in 

 Scriba's Journal, in which a pupa was not disclosed until the fourth 

 year. B.i. st. iii. 222. Pezold. 170. 



b Marsham in Linn. Trans, x. 402. 



c Meinecken found, that of several pupse of Saturnia pavonia, 

 some kept all winter in a room heated daily by a stove, and others 

 in a cold chamber, some of both parcels appeared in March (none 

 earlier), and some of both had not appeared in July, though evidently 

 healthy. Naturf. viii. 143. 



