30 Insecta. 



characters is the one which, in respect of those characters, departs furthest frora 

 the normal characters of its near relatives and ancestors: (II) secondary sexual 

 characters of c? and ? differ in their object, those of the c? being directed prin- 

 cipally towards the act of pairing, while those of the $ are directed to the duties 

 subsequent to pairing, i. c, oviposition, making and provisioning of nests, etc. 

 It has been stated that in Arthropoda and Vertebrata c^c? are provided with 

 special organs for discovering, reaching, charming and securing the $$: 

 and the author considers that in Aculeate Hymenoptera, the first and third of 

 these categories ('discovering' and 'charming') have played far the most im- 

 portant part in modifying cT structures. (III) Protection of the individual (cryptic 

 coloration etc.) may account for a few, but only a very few, of the sexual cha- 

 racters of Aculeata. (IV) The structural secondary sexual modifications of the 

 c?c? differ from those of the ?? in being more diversified in nature and less re- 

 stricted to particular parts of the body, in departing further from the normal 

 group-characters, in appearing more sporadically, and lastly in being for the most 

 part altogether absent in the 5 sex (whereas the 5 characters are mostly only 

 augmentations of features which are present, at any rate rudimentarily, in the c? 

 sex). (V) The secondary sexual characters usually exhibit very little Variation: 

 in exceptional cases they are very variable, but on the whole there is no corre- 

 spondence between the degree of abnormality of the characters and their varia- 

 bility. (VI) The parts of the Organisation which exhibit secondary sexual diffe- 

 rences, are not those parts in which the differences between allied species are 

 exhibited. 



The facts supporting these generalisations are brought together under hea- 

 dings as follows. (A) Structural modifications: relative sizes of the sexes: 

 secondary sexual modifications in (l) cf eyes, (2) cT antennae, (3) c? legs, (4) <^ 

 ventral abdominal, and dorsal apical and subapical plates: secondary sexual mo- 

 difications in (1) $ eyes and antennae (mostly negative), (2) 5 mandibles, (3) $ 

 legs, (4) $ abdomen (only few under this heading), and also (5) occurrence of 

 apterous $?. (B) Colour modifications, both in the colours of the integument 

 and of the pilosity. H. Scott (Cambridge). 



89) Perkins, R. C. L., The Races of Ändrena rosac Panz. In: Ent. Mo. 

 Mag., Bd. XXIV, Heft 1, S. 10 — 13, 1913. 



The writer deals with the distribution and Variation of this species and its 

 various races and forms in England. Three distinct races occur in England: 

 (I) Ä. trimmerana, always single-brooded, and the most abundant of all; (II) a 

 double-brooded form in which the two broods differ from one another, the spring- 

 brood being known as Ä. teutonica Alfk. and the summer-brood as Ä. rosae; 

 (III) another double-brooded form in which the broods also differ, the spring- 

 brood being known as A. spinigera and the summer-brood as Ä. anglica Alfk. 

 Thus there are 5 distinct forms in all. The two spring-forms (tetdonica and spi- 

 nigera) may occur together in the same locality, or alone in separate localities: 

 in either case the ubiquitous Single brooded race (trimmerana), which appears 

 in spring, will be found with them. The two summer-forms (rosae and anglica) 

 may also be found either in the same locality, or apart. It is very doubtful 

 whether either the 3 forms found in spring, or the 2 found in summer, inter- 

 breed. A certain amount of Variation has been observed: e. g., among many 

 hundreds of trimmerana cf from a certain district, 2 were found possessing the 

 genal spines characteristic of spinigera; but they showed no other characters of 

 that form, being in all other respects typical trimmerana. H. Scott (Cambridge). 



