a few days as free living larvae, somewhat similar to those of Culex. 

 However^ they seldom hve longer than 5 or 6 days in a jar that does 

 not contain Pistia plants. 



The pupa forms and escapes from the larval skin without causing 

 the latter to become detached from the air-supplying rootlet, the pupal 

 period ranging from 2 to 5 days, 3 being the average. The emergence 

 of the adult occurs at night, possibly during the early morning hours, 

 the pupa becoming detached from the plant and rising to the surface 

 of the water, where the pupal skins are always found. 



T. titillans is tropical or sub-tropical in its habitat, being found 

 in some parts of the southern United States, Mexico, Central and 

 South America, and the Antilles. In Panama it is at present the 

 most ubiquitous mosquito of the Gatun Lake region. Being a strong 

 flier, it travels long distances and may be met with in the jungle 

 several miles from the lake shore. It bites readily at all hours between 

 sunset and sunrise, but shuns the light as much as possible and does not 

 usually bite in broad daylight. This species is a persistent biter, 

 readily piercing even the tough cuticle of the palm of the hand, and 

 thin clothing offers but little protection against its attacks. 

 The feeding of a female sometimes continues for a period exceeding 

 10 minutes, and one specimen, kept alive in captivity for 17 days, 

 in that time took 14 blood meals. T. titillans is present in the Canal 

 Zone throughout all months of the year, but is most abundant from 

 late April to early October. 



As far as known at present this mosquito is not concerned with the 

 transmission of any disease to man or domestic animals, but should 

 it ever prove to be a vector, the only means of eliminating it will be 

 by the eradication of Pistia stratiotes, which is presumably essential 

 to its larval existence. These plants are readily killed by arsenical 

 sprays and will decay and sink in from 6 to 8 days after treatment. 

 They are remarkably free from natural insect enemies, there being 

 only one, the larva of a small moth, Samea multiplicalis, Gn., 

 which destroys large numbers by tunnelling into, and feeding upon, 

 the leaves. This, however, does not constitute an efficient control, 

 owing to the rapid propagation of the plant by means of both seeds 

 and runners. 



Snyder (T. E.). A Peculiar Habit of a Horsefly (Tabanus americanus) 

 in the Florida Everglades. — Proc. Entom. Soc. Washington, DC, 

 xix, no. 1-4; March, June, September, December, 1917: 

 pp. 141-146, 2 plates. [Received 22nd October 1918.] 



During the month of March 1917, many thousands of adults of 

 Tabanus americanus were observed in flight over one district in Dade 

 County, Florida. The flies took to the wing at daybreak ; each morning 

 they could be heard leaving the tree-trunlcs where they had been 

 resting and striking the foliage as they rose. The flight generally 

 lasted about twenty minutes, beginning with a buzzing sound that 

 gradually increased to a dull roar. Individuals hovered particularly 

 over openings in the forest or over the road, in the manner of Syrphids. 

 It is not known whether this is a mating flight. Mules in the district 

 were protected with closely-fitting coverings of sacking ; men were 



