I IO 



THE BRITISH NATURALIST. 



[May 



sarcophagus (which is curiously full of air), until he can spread his 

 wings and fly off. 



Prof. Miall has carried Prof. Weissmann's investigations a step further 

 in the excellent description of the life history and development of Chirono- 

 mus dorsalis, the " plumed gnat," to which we shall have to refer again 

 shortly. Both in Coretlira and Chironomus the metamorphic changes are 

 gradual, and extend through a portion of their larval as well as 

 pupal existence, but this is not so in the Lepidoptera, for, says Professor 

 Poulton as to these, "the formation of imaginal appendages within the 

 pupa is deferred until very late, and then takes place rapidly in the lapse 

 of a few weeks." 



In the larva of Coretlira, however, the changes do not proceed so far 

 as they do in Chironomus, and we fancy the reason for this is to be found 

 in the small size of the head and neck of the larva ; but they must have 

 extended a little, for we find immediately after the marvellously rapid 

 ecdysis of Coretlira into the pupa state that the development of the eyes 

 and the bulbs of the antennae can be clearly discerned, as well as the 

 wings and legs of the fly, by focussing through the curious tubules 

 which lie adjacent to the cephalothorax of the pupa (Fig. 4,/). 



We know of nothing in the metamorphoses of the Invertebrata so 

 rapid as this ; the nearest approach to it being the development of the 

 larval Actinotrocha into the Gephyrean worm, Phoronis, which is effected 

 by a rapid process of turning inside out. These points form some of the 

 difficulties which the late Professor Mimes Marshall admitted in his 

 lectureshe was met with in proving the "Recapitulation Theory," which 

 on the other hand seems to fit in so well with the evolution and life 

 history of the Crustaceans. 



Many of our readers who are pond hunters, or who possess a micro- 

 scope, and live in the country, must have met with the curious Bloodworm 

 often found among the roots of watercress, &c, and sometimes, where 

 there are careless servants, even when it comes to table, for the 

 hooks on its two pairs of false feet make it rather difficult to wash off. 

 No wonder it was called the " Harlequin " larva (Chironomus) from its 

 jerking and bounding leaps. When Professor Miall, lecturing before 

 the British iVssociation at Cardiff, described some of these aquatic 

 larvae, an old friend was immediately recognized. It was therefore 

 exceedingly satisfactory when the monograph of Chironomus dorsalis 

 appeared in the transactions of the Linnean Society, and all interested 

 in this subject must be urged to examine the splendid detail drawings 

 of the larva, pupa and fly made by our indefatigable friend Mr.Hammond, 

 F.L.S., in collaboration with Professor Miall, F.R.S.* 



[To be continued.) 



* Transactions of the Linnean Society, Vol. 5, part 8. 



