DONISTHORPEA. 215 



and the winged sexes of aliena in a nest on the sands in Croyde 

 Bay, North Devon, which he thought were the first taken in this 

 country 12 , but F. Smith had found it in July, 1865, on the Deal 

 sand-hills 4 , where it is still abundant. 



Schenck says he has often met with workers and pupae of D. 

 aliena in nests of F. sanguinea at Nassau 2 . 



Nests of aliena will receive and hatch both worker and female 

 pupae of nigra and vice versa, larvae being even accepted in some 

 instances. 



As with nigra, eggs laid by the workers of aliena in captivity will 

 produce workers. I have reared such workers in an observation 

 nest of D. aliena whose queen was a female D. mixta taken at 

 Wey bridge on July 10th, 1912. This nest will be referred to again 

 under the latter species, and also under D. umbrata (pp. 232, 240). 

 The winged sexes occur from July to November, though Smith 

 stated that they did not appear before the latter part of August 4 . 



Schenck gives July 13th till late in September 2 , Farren- 

 White took males in November 23 , and I have found males and 

 winged females in the nests from July 2nd to September 26th. 



Mermithogynes occur in this species D. Sharp mentions that 

 female specimens of aliena have been found with short wings, 

 but he incorrectly treats them as intermediate forms between the 

 winged and wingless females 26 . Mrazek has shown that the virgin 

 females of aliena may become infested with a worm of the genus 

 Mermis and that when this occurs the insects develop abnormally 

 small wings 36 , and Wheeler found on dissecting short-winged 

 females of D. neonigra a species closely related to D. aliena 

 taken in a colony near Manitou, Colorado, that each contained a 

 large coiled Mermis 53-55 mm. long [Journ. Experim. Zool. 8 421 

 (1910)]. 



Crawley took several short-winged females of aliena in a nest 

 under a stone at Oddington in 1900 38 , and he tells me that all the 

 winged females present in this colony were brachypterous. The 

 wing of one of these females, kindly given to me by the captor, 

 measures 4*5 mm. in length as against 10 mm. in a normal female, 

 from which it differs in no other way. 



Schenck says aliena begins to swarm later than nigra, and its 

 swarmings continue after those of the latter have ceased 2 ; he 

 records a marriage flight on September 22nd 2 . Hall noticed another 

 on August 7th, 1887, near Dover. He writes : " Being a still and 

 sultry evening, the air was literally full of males, and the ground 

 and walls covered by myriads of both sexes ; the females had 

 mostly denuded themselves of their wings in order to seek a suit- 

 able place for oviposition." 14 The females of D. aliena are equally 

 well able to found their colonies unaided as are those of nigra. 



Farren-White discovered in 1881 under a stone at Lulworth a 

 dealated female and three or four very small-sized pupae enclosed 



