42 [rdinuiry. 



sand near the sea ; the patclies were also inhabited by Mellijivs m vevsix. CaUi- 

 cera aenea F., one si^eciinen, ^ , of this veiy i"are fly was captured. It is a 

 Mediterranean g'enus, of which aenea F. and yerhuryi Verr. are the only species 

 found in (xreat Britain. 



Ischyrosyrphus laternarius Miill. ; Helophilusversv-olorY. ; Xijlota florum F; 

 Pijrophaena granditarsis Forst. ; Eristalis neinorum L. ; the beautiful var. /itn'a 

 of Eristalis intricariiis L. ; Chrysogaster chalyheata Mg. ; Volncella pellucens L., 

 very common ; Volncella inanis L., fairly frequent, though most of the 

 specimens were S- this fly is said to be associated with the hornet, l)ut I did 

 not see any of the latter ; Cono^js fiavipes L. and Conops quadrifasciata Deg., 

 which always flew in pairs, about 20 were seen in the hedge bordering the moor, 

 biit they were difficult to catch as they kept well in the hedge ; Pyrellia cyani- 

 color Zett. 



The sand dunes yielded only Anthrax ; the marshes, jjine woods and moors 

 seemed rather poor in Diptera ; the hedges everywhere swarmed with Diptera, 

 which attracted Sympetrum striolatum in immense numbers. But for the fact 

 that I had no experience and poor health, the result would probably have been 

 better still. Mr. H. S. Charbounier kindly identified my captures. — H. Audcent, 

 84, Belvoir Eoad, St. Andrew's, Bristol .- January I7th, 1917. 



Jibstrafts of ferent Sitcratitrr. 



BY HUGH SCOTT, M.A., F.L.S., F.E.S. 



ToTHiLL, J. D. "The Ancestry of Insects, w^ith PARTicur.AR refer- 

 ences TO Chilopods and Trilobite.s." American Journal of Science, Vol. 42, 

 pp. 373-387, November, 191(5. 



Various genealogical trees for insects have been put forward : inter alia, 

 the classification of Brauer ; the work of Packard deriving winged insects 

 throiigh primitively wingless forms from Myriapoda ; Carpenter's conclusion 

 (1903) that insectsand the myriopod groups Chilopoda (centipedes) and Diplopoda 

 (millipedes) all originated independently from a symphyloid stock; and the 

 heterodox theory of Handlirseh, that insects were directly derived from the 

 extinct crustacean group Trilobita, the detailed structure and development of 

 which lias become known in recent years. 



This last hypothesis Tothill considers to be very suggestive, but open to 

 objections. As shown below, he suggests rather that trilobites may have given 

 rise to chilopods, which in turn gave rise to insects : these last arising, therefore, 

 not directly but indirectly from trilobites. 



Which are the most generalised of all insects ? The Apterygote forma 

 occasionally preserve, even in the adult condition, primitive characters, such as 

 the abdominal appendages, and in certain cases (e.g., Anurida and young embryo 

 Lepisma) the tritocerebral appendages. But some of them show considerable 

 specialisation, siich as reduction of eyes and mouth-parts (certain Thysanuraand 



