866 RECORD OF CURRENT RESEARCHES RELATING TO 



states that in Sicus and Erislalis additional organs of this kind — and 

 in Musca vomitoria as many as fifty of them — occnr in the same ter- 

 minal segment of the antenna. From their structure and innervation 

 he would still regard them as sensory, but leaves the question of their 

 exact function to be settled by physiological experiment. 



Dr. H. Krauss identifies the fly-larva in which Professor Graber 

 claimed * to find an otocyst, as that of Tahanus autumnalis Linn., 

 a species remarkable in its genus for its aquatic habits in its earlier 

 stages. The organ referred to is found also in the perfect insect. 



Scales of the Lepidoptera. — In his ' Physical Description of the 

 Argentine Eepublic,'t Dr. H. Burmeister devotes a chapter to a 

 special examination of the scales of the Lepidoptera. 



After remarking that the whole life of a special observer would not 

 be sufficient to recognize the innumerable variations in the scales of 

 even a single species, and describing the general structure of the 

 scales. Dr. Burmeister comes to the question of the markings on their 

 surface, and states that notwithstanding the trouble that the question 

 has already given to naturalists, he considers himself able to say, as 

 the result of his own researches, that any difficulty is now cleared up. 

 The scales which he studied were those of different species of the 

 genus Casfnia, which has the largest of any insect. 



According to his observations the scales do not enclose any third 

 membrane, but are empty, the two membranes of which they are 

 composed not touching each other, but leaving a certain space between 

 them, a construction which is plain in the white and transparent 

 scales. Those which are coloured, contain a fluid colouring matter at 

 the commencement of the formation of the scale, which dries little by 

 little by the influence of the air, and leaves a deposit on the inner 

 surface of the two membranes, the fluid being finally replaced by the 

 air entering through the membranes, which remain soft for a short 

 time after the formation of the scale. The colouring matter seems to 

 be principally attached to the upper membrane, rendering it opaque, 

 whilst the lower one receives less of the deposit, and remains, con- 

 sequently, somewhat more transparent, and even without any deposit 

 in many insects. 



Dr. Burmeister's researches have proved to him that the fine 

 longitudinal strife belong entirely to the upper membrane of the 

 scales, and are wanting in the lower. 



The longitudinal stride are very regularly distributed with equal 

 intervals, though somewhat different in different scales. The breadth 

 of the spaces between the lines is always greater than that of the 

 lines themselves, while the lines are in general of equal breadth, 

 though there are some scales where coarse lines alternate with finer 

 ones. This distinction of coarse and fine lines the author has seen 

 plainly in scales with an indented terminal margin, and found that the 

 coarse lines correspond to the teeth of the margin, whilst the others 

 correspond to the intervals between them. 



* Loc. cit. 



t 'Description Physique de la Re'publique Argentine,' vol. v. " Lepiiloptores," 

 part i. p. 21, 8vo, Buenos-Ayres, Paris, and Halle, 1878. 



