they can extend or ^^ho^ten at will and thus make it 

 correspond with the depth of water above them. I 

 have taken these larvte repeatedly in the spring of 

 the year. 



17. Eristalis Havipes. Walker. This species has 

 the appearance of one of our common humble-bees. 

 It appears to be northern in its range. Specimens 

 have been taken at Napoleon, July 7. 1806, 



18. Eristalis tenax. Linn. Common in all parts 

 of the State, and l)esides it may be expected in any part 

 of the world. Williston gives its habitat as Europe, 

 Asia, Africa. Japan and North America. Its larvae 

 live in decaying organic substances, and, therefore 

 are valuable scavangers. The resemblance it has to 

 a honey bee has made it a conspicuous species for 

 centuries. Osten Sacken has associated this species 

 with the oxen-born bees of the ancients. 



lit. Mallota cimhiciformis. Fallen. This species 

 has been taken at Columbus in May, 1807, but does 

 not appear to be common. It has a very close re- 

 seml)lance to Eristalis ilavipes but may be easily 

 separated from that species by the strongly thickened 

 posterior femora. Some male specimens have a s])ine 

 on the hind tibia above, while in others this spine is 

 lacking. Both forms have been taken at Columbus. 

 The latter form is noticeably smaller than the former. 



20. Tropidia quadrata. Say. Common in Sep- 

 tember along the margins of ponds where water lilies 

 and various other aquatic plants are growing. Here 

 it flies from one leaf to another but resting a. great 

 part of the time. On September 8, 1808, I took 

 numerous specimens of this species. 



"21. Brachypalpus frontosus, Loew. One male 

 specimen taken at London. April 17. 1808. The 

 uniform dark color, the thickened hind femora, and 

 arched hind tibiae of the male are characteristics of 



