NiNTM B.EPORT OF THE IS TATE ENTOMOLOGIST 313 



Other Species that Hibernate Within Doors. 



There are a number of other Diptera that avail themselves of the shelter 

 and comfort of our dwellings for their protection and repose during the 

 months of autumn and winter. A German author, as quoted b}" Riley, 

 records the swarming of two other species of Pollenia, viz., P. atramen- 

 taria and P. vespillo, in the same building for several successive years. 



Mr. B. P. Mann {loc. cit.) has written: "I remember that during one 

 or two 3^ears, at a certain season, which, as far as my recollection serves 

 mie, was in April, I noticed numerous specimens of Microdon fflobosus, 

 a syrphid fly, issue from a nail-hole in a plastered wall of an apartment 

 in a dwelling house, as though the flies had passed the winter within 

 the walls of the house." 



The many interesting features attending the in-door hibernation of 

 one of the Oscinidcf — Chlorops prolijica of Osten Sacken, have been 

 presented at considerable length in my Fourth and Seventh Reports. 

 This species, however, has not yet become a common nuisance, dis- 

 agreeable as it may be to the inmates of the house that it selects for 

 its annual winter abode, as we know of its occurrence in only three 

 localities in the United States. 



Baron Osten Sacken has kindly contributed to the Fourth Report 

 above referred to (page 72) several notices of assemblages of one or more 

 species of Chlorops (they were not authoritively determined) within 

 occupied buildings in Europe, for hibernation: In one instance it was 

 estimated that eighteen millions of one species had gathered, in Sep- 

 tember, on the ceiling of a botanical conservatory in Warsaw. 



It is quite probable that numbers of the common house-fl}^ (females) 

 pass the winter within the houses that they have been previously 

 occupjang, hidden away within crevices about the windows, but it is not 

 recorded that thej'' ever assemble in companies at such times, either for 

 -warmth or from social instinct. 



Early Stages of Pollenia rudis. 



It is not known that the early stages of this insect have been observed 



in this country, or minutely anywhere. R. Desvoidy has given the 



general statement of the European PoUenias, that their eggs are laid 



in decomposing animal and vegetable matter. According to Macquart, 



their larva* develop in the manure pile and cow droppings — "sans le 



ferrier et les bouzes." 



Description of the Fly. 



The description of this fly, left in MS. by Dr. Harris under the name 



of Masca familiar is, as previously referred to, is as follows: 



- Head somewhat prominent in front, of a dirty yellow or tawny color 

 with a silky lustre, and distinct black bristles; eyes in the male conni- 

 189:;]. ^ 40 



