v POLYMORPHA GLOW-WORMS 251 



sides of the body, and hence are called, it is said, in Paraguay 

 the railway-beetle. We may refer the reader to Haase's paper 1 

 on the subject of these " larvae," as we can here only say that it 

 appears probable that most of these creatures may prove to be 

 adult females of the extraordinary group Phengodini, in which it 

 would appear that the imago of the female sex is in a more larva- 

 like state than it is in any other Insects. The males, however, 

 are well-developed beetles ; unlike the males of Lampyrides, in 

 general they have not peculiar eyes, but on the other hand they 

 possess antennae which are amongst the most highly developed 

 known, the joints being furnished on each side with a long 

 appendage densely covered with pubescence of a remarkable 

 character. There is no reason to doubt that Haase was correct 

 in treating the Insect we figure (Fig. 129, B) as a perfect Insect ; 

 he is, indeed, corroborated by Eiley. 2 The distinctions between the 

 larva and female imago are that the latter has two claws on the 

 feet instead of one, a greater number of joints in the antennae, 

 and less imperfect eyes ; the female is in fact a larva, making a 

 slightly greater change at the last ecdysis, than at those previous. 

 It is much to be regretted that we have so very small a know- 

 ledge of these most interesting Insects. Malacodermidae are 



O O 



probably the most imperfect or primitive of all beetles, and it 

 is a point of some interest to find that in one of them the 

 phenomena of metamorphosis are reduced in one sex to a 

 minimum, while in the other they are presumably at least 

 normal in character. 



Numerous larvae of most extraordinary, though diverse, 

 shapes, bearing long processes at the sides of the body, and 

 having a head capable of complete withdrawal into a slender 

 cavity of the thorax, have long been known in several parts of 

 the world, and Dr. AVilley recently found in Xew Britain a 

 species having these body-processes articulated. Though they 

 are doubtless larvae of Lampyrides, none of them have ever been 

 reared or exactly identified. 



A very remarkable Ceylouese Insect, Dioptoma adamsi 

 Pascoe, is placed in Lampyrides, but can scarcely belong there, as 

 apparently it has but five or six visible ventral segments ; this 

 Insect has two pairs of eyes, a large pair, with coarse facets on 



1 Deutsche ent. Zeitsclir. xxxii. 1888, pp. 145-167. 

 - Ent. Mag. xxiv. 1887, p. 148. 



