130 
[November, 
‘‘ Beitrage,” pp. 230 — 232) ; (o) another point in which G. raphani 
agrees with other parthenogenetically reproductive arthropods is its 
many-broodedness in a season. There may be three or four generations 
in direct succession in the year, and there is a constant succession of 
eggs all the time. In this it appears to differ from any of its allies 
with which I am acquainted. (6) Finally, the case of G. raphani 
would seem to be one of true parthenogenesis in its most restricted 
sense — the same beetle which in the unimpregnated state lays sterile 
eggs, with here and there one capable of development, after receiving 
the male element, laying eggs which are fertile and develop in the 
ordinary way. That is to say, the ova are true ova, and not pseud-ova 
or buds, the parent a perfect female and not an “Amme” like the 
summer Aphis. 
Milford, Letterkenny, Ireland : 
September 22nd, 1880. 
DR. F. MULLER’S DISCOVERY OF A CASE OF FEMALE DIMORPHISM 
AMONG- DIPTERA. 
BY BARON C. R. OSTEN-SACKEN. 
We owe to Dr. Fritz Muller, in Brazil, the important discovery 
of the hitherto unknown larvae of the Blepharoccridce, a very aberrant 
Family of Diptera Nemocera , of which a dozen species are at present 
known, remarkable for their sporadic distribution nearly all over the 
world (Europe, Ceylon, North and South America). In connection 
with this discovery of the larvae, Dr. Muller publishes another very 
interesting and novel fact, the existence, in the species observed by 
him (which he names Paltostoma torrentium ), of two sets of females, 
the one of which has the organs of the mouth built upon the plan of 
the trophi of blood-sucking Diptera , while in the other, as well as in 
the male, the mandibles are wanting. These females differ from each 
other besides, in the size of the eyes (separated in both cases, while 
they are contiguous in the male), and in the structure of the last 
tarsal joint. For details I refer to Dr. Muller’s circumstantial and 
conscientious article in the October Number of the German periodical 
“Kosmos,” and will only add, that these flies were obtained by Dr. 
Miiller in large numbers by cutting open nearly ripe pupae, but, as it 
seems, were never found in the open air. 
As I have paid some attention to the Family of Blepharoceridce , 
and am the only person who knows de visu all the described species 
(always rare in collections), I feel bound to make the following re- 
marks, which suggested themselves to me in reading the above-quoted 
article. 
