158 



THE ENTOMOLOGIST. 



'British Plies,' is unable to supplement the work of Haliday. 

 Coming to the year 1894, its rediscovery almost simultaneously 

 by Carpenter (from Killiney Bay, Co. Dublin) and Chevrel (from 

 the coasts of Calvados ; he calls it Clunio syzygialis) filled some 

 of the blanks in the life-history of the insect. Both these 

 authors discovered the eggs, the larva, and the female. The 

 eggs are narrowly spindle-shaped, and are enclosed, like those 

 of Chironomus, in a gelatinous green tube. The larva is green, 

 and possesses no ventral blood-gills ; it lives among Cladophora 

 and other algae in the rock-pools, and is therefore truly marine. 

 It is worthy of note that blood-gills are similarly wanting in 

 Chironomus oceanicus, described* by Packard (Proc. Essex Inst. 

 1868, pp. 41-46) from Salem Harbour, as well as in the larvae I 

 have met with at Port Erin, and in some of the fresh-water 

 species. The female may be fairly described as apterous, for 

 what remains of the wings is reduced to tiny vestigeal appen- 

 dages ; she crawls about over the rocks and weed at low water, 

 and during pairing the male flies about with her held in a 

 straight line with his own body by means of his strong claspers. 

 A full account of the habits of both sexes will be found in 

 Chevrel's paper.* I might mention that in Halirytus amphihius, 

 discovered by Eaton in Kerguelen Land, the wings are similarly 

 vestigeal ; although placed in the Tipulida?, S^iaiv considers 

 that it is probably a Chironomid. The degeneration of the 

 wings in the female has been described as the result of complete 

 adaptation to a littoral habitat ; for in so tiny and highly fragile 

 an insect, if wings were present, the chances of being blown out 

 to sea would be very great, and an appreciable numerical 

 deterioration of the species would result from the destruction of 

 the eggs. The mouth-parts are very rudimentary in both sexes, 

 a feature which distinguishes the imagines from those of other 

 Chironomids. 



Besides marinus, two other species of Clunio have been de- 

 scribed, namely, G. adriaticus by Schiner, who states that it is 

 found on the sea-shore among sea products of all kinds, and that 

 Fraunenfeld found it amongst colonies of Mytilus minimus ; and 

 C. hicolor by Kieffer from the French coasts. 



Chevrel gives a few observations upon the internal anatomy 

 of the Clunio larva, and Giard has described its tracheal system. 

 Nothing is known of the anatomy of the imago. 



In conclusion, I wish to state that I submitted this short 

 article to Mr. G. H. Verrall, and I am indebted to his kindness 

 in reading it through, and offering a suggestion upon it. 

 Zoological Laboratory, University of Birmingham. 



* An interesting account is also given by Carpenter in ' Knowledge,' 

 1901, pp. 197-8. 



