222 Prof. J. O. Westwood on some 



covering of the larva, the pupa not having had sufficient 

 strength entirely to get rid of the larva skin, so that the 

 perfect insect has its head, for instance, enveloped not only 

 in the cejjhalotheca of the pupa but also in that of the 

 larva. This form of monstrosity constitutes all Lacor- 

 daire's fifth division " Monstres par arret de developpe- 

 ment " (Introd. ii. p. 441), of which he was only 

 acquainted with two instances (p. 442), viz., Mueller's 

 Phalcena Heteroclita and Wesmael's Nymphalis Populi, 

 noticed below. 



COLEOPTERA. 



Cybister limbatus. — A specimen of this water beetle 

 was captured by Mr. J. C. Bowring, swimming in water 

 at Hong Kong, having the head of the imago replaced 

 by that of the larva. The specimen is represented in 

 PL VII. figs. 1 and la. It is noticed by Mr. F. Smith, 

 " Proc. Ent. Soc. Loud.," ser. 2, vol. iv. p. 34, and by 

 myself as a species of Dytisctis in the " Entomol. 

 Monthly Mag.," No. 82, p. 239. The specimen is now in 

 the British Museum. The anterior part of the head of 

 the larva is broken off, but the very narrow neck has pre- 

 vented the development of the widened jugulum of the 

 imago. 



Hydaticus bimarginatus. — Dr. John L. Leconte in- 

 formed me that a specimen of this beetle retaining the 

 head of the larva is in the collection of Dr. Helmuth, of 

 Chicago. 



Calyptocephalus fasciatus (G. R. Gray, in Griff. 

 Ass. K. Ins., pi. xxxix. f 5). — PI. VII. fig. 2 represents a 

 specimen of this Brazilian species of Malacoderms which 

 has not had sufficient strength to throw off the prothoraco- 

 theca of the pupa, which still remains as a large white 

 regular-shaped scale concealing the head and prothorax 

 when seen from above. Fig. 2a shows the lateral view of 

 the anterior part of the body, showing the prothorax dis- 

 engaged except at its anterior part. 



LEPIDOPTERA. 



Gastropacha quercifolia. — A specimen of this moth, 

 having the head entirely enveloped in the cephalotheca of 



