598 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XVIII. 



2. Caenocoris marginatus (Thunberg.) 

 PL figs, 1—7. 



This form belongs to the Myodochidee (or " Lygaeidao " of some authors) and 

 has much the same geographical distribution as the Dindymus and is also with- 

 out any offensive smell. The only near ally of which the metamorphoses are 

 fairly known is the American Stalagmostethus turcicus. The eggs observed were 

 deposited about the middle of December. 



The period from hatching to maturity was fifty-three days ; in wet seasons 

 it is perhaps much less. The exact number of moults was not observed. 



The ova are deposited on the upper side of a leaf in a semi-circular batch of 

 about twenty, touching one another. When first laid they are pale yellowish- 

 red, deepening to blood-red, the caps white (PI. fig. 1-2) the entire egg usually 

 splits longitudinally, though sometimes the upper part of the shell breaks trans- 

 versely some distance below the cap. Nymphal instars. — When first hatched the 

 nymphs are blood-red, antennae and legs brownish. Abdomen almost globular 

 in section. They feed on vegetable juices, especially Toxocarpus wightianus, 

 Hook, and Am., a twiner vary common in South China. The labium reaches to 

 about the middle of the abdomen, gradually lengthening and reaching beyond 

 the apex in much about a week. The bug is less globular in section, when 

 about one-fourth of an inch long, the legs and labium being black, the latter 

 again reaching only to the middle of the abdomen (PI. fig. 3.) When about 

 four weeks old, the tegminal pads are reddish-brown and fairly distinct 

 (PI. fig. 4-5). At five weeks they are black. 



To facilitate the final moult, the bug hangs from a twig, and occasionally 

 brings the hind legs over the back, scraping them down the tegmina towards the 

 pearly white membrane (fig. 6). In about three hours after this moult is 

 accomplished the membrane becomes dark smoky, and the red colour of the 

 other parts darkens. In about eight hours the change of colour is complete 



(%. n 



Explanation of Plate. 



Dindymus sanguineus, ova. 



First nymphal instar. 



Fifth nymphal instar. 



Eighth nymphal instar. 

 Adult. 



Caenocoris marginatus, ova. 



The same, enlarged. 

 ... First (?) nymphal instar (about a week old). 



A later instar (about four weeks old). 



The same in profile. 

 ... Newly emerged adult. 

 ... Adult with matured colouring. 



