76 A YEAR OF COSTA RICAN NATURAL HISTORY 



black mud so that we were driven to look for larvae in other 

 pools, particularly one in the lane to the east, the Calle de 

 P. Peralta. A lull in the rains caused the pools to shrink 

 considerably about the middle of November, but on Novem- 

 ber 29 the pools were full again and all the potreros soaking 

 wet. On February 19 we found both these lanes much drier 

 than they had been for months. Even the deeper pools in 

 both which served as homes for aquatic animals since August 

 had now no water and hardly any spots of wet mud. By 

 February 24 the Shady Lane was dry and beginning to 

 resume the conditions it presented when we first knew it. 

 The bottom of what had been the deepest pool was now 

 covered thickly with yellow-flowered Jussiaeas. P. dug 

 down into some pockets of soft wet mud still remaining to 

 see if any traces could be found of the dragonfly larvae so 

 common here in the wet season, but without success. A 

 similar trial in the dried pool in the next lane east, a prolific 

 source of larvae in that period, was also a failure, although 

 the empty shells of snails, former inhabitants of the pool, 

 were there. By March 11, 1910, the conditions of dryness 

 approached those found on our first visit to the Shady Lane 

 nearly a year before. 



On May 27, 1909, when returning through the Shady Lane, 

 I caught a butterfly which to my great astonishment, as I 

 was taking it out of the net, thrust out from each side of the 

 hind end of the abdomen a brush of blackish hairs looking 

 like an ordinary camel's hair brush. I immediately thought 

 of the two brushes as possibly odor-producing organs to 

 diffuse some disagreeable smell which would act as a means 

 of defense, but I could not detect any odor whatever. I 

 took the butterfly home alive and kept it so until the after- 

 noon of the following day. As I took it from the envelope 

 some hours after catching it the butterfly voluntarily thrust 

 out its brushes once, and again on the next day when I began 



