fhi/lcrjl// Mi(/r(ili()tis ui lir'disJi Giiimia. '^'M 



think i'liey vvciv. so thick as to constitute a cloud." Jle 

 adds, " The insects were flyiufi; in a soutli-casterly direction ; 

 the direction of the wind being north-east." 



He further states : " As far as my observations extend 

 I have noticed that the butterflies always appear during 

 the months of June, July, and August, and sometimes their 

 migration continues in the early part of Septend)er if the 

 weather remains dry. The flight ceases if it should rain 

 during the migration. The insects always travel at right 

 singles to the wind." These observations were nuuh^ in the 

 Noitli-West J)istrict at Issororo, and may be taken to apply 

 to Calli(lr//(is. 



Pieris phileta K. 



11. My father suj)plies the following observations on a 

 large migration of Pieris philela V., which he witnessed on 

 the Courantyne Coast, Berbice, in September 1919. 



About the middle of September he saw a migration of 

 butterflies taking place at Albion Magistrate (Jourt, which 

 is about 12 miles from New Amsterdam. The insects W(^re 

 presejit in very large numbers, and in giving an idea of the 

 density he estimated that there were about 10 insects to 

 the square yard, and added that to say they were like falling 

 snow would certaiidy describe the appearance. The insects 

 were present as far down the coast as Jiranifield, which is 

 4 miles fi'om New Amsterdam, so that the swarm was about 

 Smiles wid(\ Tlu^ insects were (lying tovviudsthe foi-eshore 

 • — that is, in a iiortherly direction. This would be across 

 the prevailing wind, which is usually north-easterly, but on 

 this point he can. give no delinite information. 



On the following day he again observed them at Whim, 

 about G miles furtlier up the coast, and about 18 miles fi-om 

 New Amsterdam. The insects were just as numerous as 

 on the previous day, and on this day several were collected 

 against the glass windows in th(^ rest house. They all 

 proved to be Pieris 'philrla V. Of eighteen insects collectcnl 

 in this way ten were males, while eight were females. 

 This migration took ])lace between 8 and 11 a.m. 



On making inquiries from the Police in the district he 

 was informed that such migration had been going on for 

 the past week or ten tlay.s, and tha.t they often occurred in 

 that district. 



During this year I have bred tlu; insect in (Georgetown 



TRANS. KNT. SOC. [,ONIJ. 1920. I'AKTS III, IV, V. (AI'|{.'2I) Z 



