52 SUMMARY OF CURRENT RESEARCHES RELATING TO 



dissolve ; tluis reverting to the embryonal type. Tlio two basal 

 trunks increase in length and form the IMalpighian vessels of the 

 moth. 



From the dissection of a large number of both micro- and macro- 

 Icpidoptera, the author considers that three types of Malpighian 

 vessels can be established in Lepidoptcra, 



1. The normal type of six Malpighian vessels, 



2. Tlie emhrtjonal (or atavic) type of two Malpighian vessels, as in 

 Tineola hisellieila Huram., Tinea pellionella L., and Blabophanea 

 rtisticclla Hb. 



3. An abnormal type in which the Malpighian vessels take a very 

 arborescent arrangement, as in Galleria cere ma L. 



Action of Ammonia upon Lepidopterous Pigments,* — G. Cover- 

 dale calls attention to the changes of colour produced on the pigments 

 of some lepidoptera, when subjected to the action of ammonia. 

 Melanargia galothea when submitted to a saturated aqueous solution of 

 ammonia turned a beautiful primrose yellow, but regained its normal 

 white colour as the ammonia was allowed to evaporate. The black 

 pigment remained unchanged throughout. Solution of potassium 

 hydrate gave the same result. Other alkalies, such as solutions of 

 sodium hydrate and barium hydrate were tried and gave similar 

 results, the only difference being that w^ith the fixed alkalis the 

 primrose coloration was permanent, whereas with ammonia it w&s 

 necessarily fleeting. By the use of acids the pigment was restored 

 to its natural white colour. Whenever an exactly neutral liquid 

 was employed or one in which the acid predominated, the pigment 

 remained unchanged : thus this pigment is a good test for alkalinity. 

 Experiments on other lepidoptcra gave varying results, not a single 

 species in some genera being affected by the treatment. Of the genus 

 Lyccena some species remained unaltered, whilst others were affected. 



Comparative Chaetotaxy.t — C. E, Osten-Sacken proposes the 

 term chajtotaxy (in analogy to i^hyllotaxy) for the arrangement of 

 characteristic bristles (macrochfetfe) on the diff'erent parts of the body 

 of the Diptera, and divides this order into two groups according to 

 the presence or absence of bristles : — Diptera chfetophora and Diptera 

 eremochseta. 



Bristles easily fall off, and the scars which they leave are not 

 always recognisable, so that statements about chfetotaxy must be 

 made, as well as received, with some caution. The author gives 

 reasons for believing that the macrochastfe are organs of orientation, 

 connected with the nervous system, being in their useful action not 

 unlike the whiskers of a cat, and he further points out that the 

 faculty of poising seems to be connected with contiguous eyes in the 

 male sex. Thus the Diptera eremochfeta are for the most part 

 holoptic in the male sex and aerial insects ; the Diptera chaBtophora, 



* Nature, xxx. (1884) p. 571. 



t Trans. Entora. Soc. Lond., 1884, pp. 497-517 (^fig.) (for the most part 

 previously published in MT. Miinch. p]ntum. Ver., v. (18S1) pp. 121-38, and 



Wien Entoni. Zeit.. 1882, p. 91). 



