18 THE entomologist's RECORD. 



the Haye Wood, near Knowle, in May. I have also bred this species 

 from my Lasiits fuliijmosus nest. Some species of the genus Linwsina 

 are therefore associated with ants. The larvae probably feed in decay- 

 ing vegetable matter and refuse in the nests. 



Medeterm truncorim, Stnh.^ — A specimen was bred out of my F. 

 rufa observation nest from Weybridge, in March. 



Corynoptera, sp. ? — A species of this genus was taken in the debris 

 of a Formica rufa nest, at Weybridge, in May. 



Sciara, sp. '? — Several specimens of a small species of this genus 

 were bred out of my Tetramonum caeapitam nest from Whitsand Bay, 

 in February and April. 



Microdnn luntabilis, L. {see pi. ii., tigs. 1-3). — I am, unfortunately, 

 unable to add much to the knowledge of the habits of the larva of 

 this species. During my absence this summer, my Formica fusca nest 

 was first allowed to get too dry, and then watered too much, with 

 the result that the nest was attacked by moiild, and the whole of the 

 contents destroyed. As I have now no more material, it is perhaps 

 as well to publish such observations as I have been able to make. 

 On April 18th, 1907, I found a nest of F' or mica fiisca under a stone 

 at Porlock. On the underside of the stone was a fiillgrown larva of 

 Microdon miUabilis, another which had just pupated, and an empty 

 pupa-case. The pupa developed the two little horns which it bears, 

 between April 22nd and 23rd, and hatched on the morning of May 

 21st. The fiy was walking about at 3 p.m., the wings not having 

 developed ; by 6.30 p.m. the wings were fully grown. The larva 

 pupated on April 24th, one horn was piit out on May 4th, and the 

 other showing on May 5th, but this horn was never fully developed, 

 and the fly never hatched, though its body could be seen inside the 

 pupa-case. 



On April 19th, 1907, I found another nest of F. fusca, also at 

 Porlock, under a stone ; this contained a number of Microdon larv^, 

 on the stone and in the galleries of the nest. I dug up the whole nest 

 with two deiilated queens and a lot of workers, and when I got home 

 fixed them all up in a glass bowl half full of sand, in my study. One 

 larva pupated on the side of the bowl on April 24th, and the fly 

 hatched on May 27th. Whenever I hfted up the clump of earth which 

 covered the nest in the bowl, the Microdon larvae were always to be 

 seen in the bare galleries of the nest, among the ants. This I did at 

 various times, from May to December, 1907, and January to June, 

 1908. Occasionally a larva came up on to the top of the nest, and 

 crawled about, and then returned again. In April, this year, the 

 queens had laid a number of eggs, which the workers used to bring up in 

 the sun. On July 15th and 18th, two Microdon larvae came up and 

 pupated against the glass side of the bowl. At different times I took 

 larvae out to exhibit (at the Royal Society, and the Conversazione 

 Ent. Soc), and to be photographed. I also isolated specimens with their 

 hosts in plaster nests. I have written in my note-book, May 7th, 

 1907 : " The ants [F. fusca) appeared to gently bite at the larvfe, but 

 not in any way to attack them." I also introduced them to specimens 

 of F. rufa and F. san(jiiinea, but these ants appeared not to notice them. 

 I sent a larva this year to Mr. Grosvenor, of the Oxford Museum, to 

 dissect. He writes, " there was no solid food in the fore- 

 part of the gut, and very scanty brownish faecal matter in the 



