1914] The Ottawa Naturalist. 137 



within a foot or two of the surface while one, viz., L. rugosa, 

 was found at depths varying from 47 to 91 inches. Mention was 

 also made of the remarkable manner in which skunks sought 

 out the larva? for food, thus doing much good. An interesting 

 discussion followed on the habits and food of skunks in general. 



Mr. Sladen exhibited twelve species of wasps of the genus 

 Odynerus taken in the Ottawa district and described the habits 

 of 0. spinipes, a European species. It provisions its cell with 

 small green caterpillars. The egg is attached to the roof of the 

 cell by a thread so that it is not disturbed by the wriggling 

 victims. He also show-ed a parasitic bee, Coelioxys rufitarsus, 

 with its host, Megachile latimanus, a leaf-cutter bee, and ex- 

 plained how, according to Graenicher, the parasite pierces the 

 leaves lining the cell of the Megachile by means of its conical 

 sharp-pointed abdomen, and inserts its egg. The Coelioxys larva 

 is at first provided with enormous mandibles with which it kills 

 the Megachile larva, but after the first moult the mandibles are 

 of the small size found in other bee larva-, and thence forward it 

 feeds entirelv on the pollen that the Megachile has provided. 

 Mr. Harrington remarked that in Ottawa, as in England, 

 Megach He is verv "fond of cutting circles out of the leaves of the 

 garden rose to line its cells. It also often chooses maple leaves. 

 He had noticed that if the surroundings of a solitary bee's or 

 wasp's nest were disarranged the insect could not find its way in. 

 It seemed to have committed to memory every detail; this was 

 done by circling round the spot many times. Mr. Sladen said 

 that aueen bumble bees he had got to lay eggs in captivity, 

 when allowed to fly, never returned, though they marked the 

 spot carefullv, and he believed they lost the power to learn the 

 position of their nest as soon as they began to lay. 



Mr. Strickland spoke upon the subject of parasites in 

 Simulium larvae. After briefly describing the acquatic habits 

 and structure of the early stages of the Black fly, and pointing 

 out the interest that is centred upon this fly as the possible 

 carrier of the human disease Pellagra, he gave an account of 

 the parasites he had found infecting their larva? in the streams 

 in the vicinity of Boston, U.S. These consisted of a worm and 

 various protozoa, all of which were fatal to their larval host, 

 and occurred in sufficient numbers to be of considerable economic 

 value. The worm is a species of Mermis that inhabits the 

 abdominal region of the body cavity, where it lives coiled up 

 and almost motionless absorbing the body fluids of its host, till 

 the latter is full grown. It then ruptures the skin and escapes, 

 killing the larva in the process. When the worm only is present 

 it is 3 cm. long, or about three times the length of its host. 

 As manv as 12 were found in one larva, in which case thev all 



