THE OOLOGIST. 



167 



.nvestigations was conducted on Me- 

 morial Day, May 30, 1904. Results of 

 investigations briefly stated aie as fol- 

 lows: 



Several "spotted" sets, consisting of 

 four and five eggs, with incubation 

 fresh to advanced, had been collected, 

 and in each nest — all feather lined — 

 were noticed ants and small worms 

 (larvae), some nests having only the 

 larvae and others ants, but in several 

 ants and larvae were mixed. 



The larvae is athin, slender "worm," 

 averaging three-eights of an inch in 

 length, and in color a pale brown to 

 almost white. The ants were small 

 and of a reddish color. They were 

 found also in nests containing unspott- 

 ed eggs and in grassy-lined nests. The 

 larvae were found only in feathery-lined 

 nests, being more numerous in thos^e 

 lined with duck and geese feathers, 

 and presumely feed on the matter in 

 the shafts of the feathers. The marks 

 on the eggs are made by these "wig- 

 glers', as following results will show. 



The egg when first laid is damp and 

 would easily absorb marks of dirt be- 

 ing porous, when any dirty "worms" 

 crawled over them. An experiment to 

 ascertain whether the marks were made 

 by these larvae proved satisfactory. A 

 nest containing 5 immaculate eggs, in- 

 cubating advanced, was placed in a 

 nestful of wriggling "worms" but after 

 5 minutes of expectant watching we 

 failed to discern any marks on the eggs 

 although many of the wrigglers had 

 crawled over them. They were removed 

 and placed in an ant-infected nest with 

 the same results. My experiment I 

 thought was a failure and I began to 

 feel disappointed when a happy thought 

 struck me. It was to wet or dampen 

 the eggs, which I did, and replacing 

 them iu the larvae-infected nest I soon 

 had the satisfaction of proving that the 

 marks were made by the larvae, for 

 every one that crawled over the eggs 

 left dirt marks upon them. Removing 



the eggs and wiping off the marks, I 

 rewetted them and placed them in an 

 ant infected nest, but though left in it 

 for about ten minutes, during which 

 time they were fairly over run with 

 ants, no traces of dirt marks were dis- 

 cernible upon them. These experi- 

 ments demonstrate that the dirt marks 

 on "spotted" Bank Swallow's eggs are 

 made by the larvae of a species of in- 

 sect. 



Being a poor entomologist I can not 

 name the ant nor the larvae, and not 

 having no small vials, which I general- 

 ly carry with me, I could not bring any 

 home for identification. The larvae is 

 presumely that of a dipterous insect, 

 probably that of a small horsefly which 

 infest Bank Swallow's nests. These 

 small flies fairly over run some nests 

 when they contain young and make 

 life miserable for the helpless birds, 

 and often compel the birds to abandon 

 their young, leaving them to die a 

 horrible death, being literally eaten 

 alive. There are other kinds of vermin 

 that infect the burrows and nests, as 

 well as the birds also rendering their 

 lives miserable. The results of my in- 

 vestigation proves only that the marks 

 on the eggs I collected were made by 

 larvae of a species of insect. They are 

 probably caused by other kinds of ver- 

 min which I did not find in the nests 

 that have come under my observations. 



My observations are far from being 

 complete on account of the distance I 

 live from the colonies and lack of 

 opportunity for investigations. This 

 year I investigated no further in the 

 matter, in fact, did not do any collect- 

 ing whatever in New Jersey. 



Next year shall positively investigate 

 the cause of the vermin infected nests 

 and the spotted eggs. 



Richard F. aliLLER, 

 Philadelphia, Pa. 



This is quite in line with my 

 suspicions on this subject.— Editor. 



