POLLINATION OF THE BRITISH PRIMULAS. 119 
LEPIDOPTERA. 
Gonepteryx rhamni (L.), fairly often. 
COLEOPTERA. 
Homalium florale Payk., abundant, creeping about the flowers. 
In regard to the Bee-flies, belonging to the genus Bombylius, already 
mentioned several times : at least three species (two British and one Con- 
tinental) visit all three species of Primula so freely that they deserve special 
notice here. 
These insects, though very bee-like in general appearance, belong to the 
Diptera *. They are adapted—in the main, at all events—for sucking 
nectar. This they do by means of a long thick proboscis, which is carried 
permanently stretched out straight in front of the insect, even during flight, 
and is never coiled, as in the case of bees f. This proboscis is quite long 
enough to reach the nectar of (and, therefore, to pollinate effectively) at 
least the smaller flowers of all our Primulas; and there can be no doubt 
that (as Prof. Weiss has remarked) this insect is “an active agent in 
the pollination of the Primrose” 1. 
The Bombylii come abroad in April and May, when both the Primrose and 
the Oxlip are in bloom. To the former, at any rate, they are remarkably 
constant, seldom visiting any other flower, as Prof. Weiss has remarked §. 
I have very often watched the insect at work. In Devonshire, Archer Briggs 
says that one species “often? visits the Primrose, from which it “seems to 
obtain a great deal of its food.” Knuth || says that all the three species visit 
the flowers, “but only those with a particularly-long proboscis are able to 
get at the nectar.” Very much to the point are the remarks of Prof. Weiss, 
who says, as a result of his observations already described T, that Bombylius 
major— 
was the most regular of all the visitors [the others being four species of Bee], 
having been observed on seven days out of the eight; and, on the occasion when he 
was not observed, I think this was due to my visit being earlier than usual (4. e., 
before 11 a.m.), [when] a fresh wind from the north-west was blowing. 
The Bombylii show amazing activity, even for insects, their movements being 
rapid in the extreme, An individual, when visiting Primula flowers, does 
so after the graceful manner of the humming-bird hawk-moth, hovering for 
a time, almost motionless, just above the flower, its thick straight proboscis 
fully extended, and its wings vibrating so rapidly as to be almost invisible. 
* [ have elsewhere spoken of them, in error, as Hover-flies (Syrphide). 
+ Müller says (Fertil. of Flowers, p. 43) that their probosces are fitted “for boring into 
succulent tissues” and that they “restrict themselves to the juices of flowers;” but Major 
E. E. Austen, of the British Museum (who has kindly assisted me with information), doubts 
whether they are capable of being used for any such purpose. 
t New Phytol. ii. p. 101. 
§ Op. et loc. cit. 
|| £ Flower Pollination,’ iii. pp. 66-71. 
« New Phytol. ii. (1903), pp. 100, 101. 
