Iv 



1. A male Perrhybris Pyrrha (from Mr. Hewitson's collection) having 

 the under side of the right hind-vving coloured like the female, which mimics 

 a species of Heliconia. 



2. A specimen of XymjjhaUs Populi with larval head. 



3. A specimen of Dytismis viarginalis (original in British Museum) 

 with larval head, and one of Helojjhilus pendnlus similarly deformed, two 

 specimens of this last e.xample of imperfect development being in the Hope 

 Collection at Oxford. 



Prof. Westwood remarked with regard to monstrosities that although in 

 such cases among the higher animals the head parts often appeared 

 duplicated, this very rarely appeared among the Arthropoda. He was 

 inclined to regard gynaudromorphism as the result of the coalescence of 

 two ova in the female insect, and the subsequent suppression of all the 

 characters of the one sex but those retained in the imago. 



Mr. H. T. Stainton raised the question whether many cases of gynau- 

 dromorphism might not be explained by atavism, i.e., by partial reversion 

 to ancestral characters. 



Mr. M'Lachlan exhibited a series of cases of the larvae of Trichopterous 

 insects forwarded to him by Dr. Fritz Miiller, of Blumenau, Santa 

 Catharina, Brazil. Several of the forms, of minute size, were evidently 

 those of Hydrojjtilidai. Another form was in black, slightly curved, 

 tapering tubes of horny texture, and pertained to Setodes or something 

 allied thereto. Another (of uncertain location) of considerable size was 

 composed of nearly entire small leaves arranged longitudinally. Lastly, 

 there was one, composed of pieces of leaves, which Dr. Miiller stated had 

 the peculiar habit of occurring on trees in the water that collects between the 

 leaves of BromelicB, m which tadpoles, the larvae of dragon-flies, and other 

 aquatic animals were also to be found. In coimection with this latter habit 

 Mr. Bates informed him that rain-water collects at the bases of the leaves 

 of these plants and remains there for nine months out of the twelve. 

 There was also a photograph of a number of cases stated by Dr. Miiller to 

 belong to some species of Hydropsijcludcc, of which the- larvae "make a 

 funnel-shaped entrance to their houses with a net of which no spider need 

 be ashamed." Generally many of them build close together, so as to 

 intercept anything eatable which may come down the rivulet. Concerning 

 some other cases which Dr. Miiller referred to the Trichoptera, Mr. 

 M'Lachlan was doubtful if such was their true position.* 



The Rev. A. Eaton suggested that they might possibly belong to the 

 Diptera, the larvae of some aquatic species of which were known to 

 manufacture somewhat similar cases. 



* A more detailed account of these and some other cases of caddis-flies will be 

 published by Dr. Miiller in the ' Archives do Museo Nacional de liio de Janeiro.' 



