22 BUIjLETIN 15 7, U. S. NATIONAL MUSEUM 



CASUAXS (13) 



Argifnnis aphrodite. 

 Polygonia propne. 

 Strymon Ontario. 

 Phoehis eubulc. 

 Papilio marccllus. 

 Papilio troilus ilioneuii. 

 Cecropterus cellus. 



Erynnis sassacus. 

 Atrytonopsis hianna. 

 Poanes viator. 

 Lerema accius. 

 Prenes ocola. 

 Calpodes ethlius. 



The butterflies listed as casuals should perhaps be described as of 

 undetermined status. Papilio marceJhis was common locally in the 

 District area up to about 20 years ago and frequent up to 4 or 5 

 years ago. It has now almost completely disappeared. It is still 

 to be found as a rather frequent butterfly early in spring in the 

 region between Cabin John and Great Falls, Md., but it disappears 

 from this section during summer. 



Polygonia progne^ Stryirwn Ontario., Erynids sassacus., Atrytonop- 

 sis hianna.) and Poanes viator are all known from single occurrences. 

 All of them are northern, or at least range far to the northward of 

 the District. The}' are either intruders from the mountainous coun- 

 try to the northwest or, which seems to me more likely, species which 

 are disappearing from this region. The same may be said of Argyn- 

 nis aphrodite, Incisalia augustinus, and Lerema accius. The first 

 of these is known from three specimens, the second from two, and 

 the third from several. Cecropterus cellus., Prenes ocola, and Cal- 

 podes ethlius are southern species which might be expected here. 

 But I suspect that the last, and possibly the last two, are from time 

 to time introduced on plants. Papilio troilus ilioneus may be simply 

 a variant from Papilio troilus troilus parents. The appearance of 

 more or less typical representatives of unexpected forms in this 

 manner is not unusual. 



One of the most curious phenomena connected with the local but- 

 terflies is the production by three species in the late-summer broods 

 of highly colored " wet " forms, which, so far as is known, are always 

 killed off during the winter, only the " dry " forms surviving. These 

 three species are : Junonia lavinia, Pyrameis atalanta, and Pyrameis 

 carrdui. 



The District butterflies that are sufficiently known locally may be 

 classified according to their several types of habitat as follows : 



OOOUKRING GETMEE^VI-LY IN OPEN COUNTKY 



Basilarcliia archippus. 

 Junonia lavinia. 

 Pyrameis virginien sis. 

 Pyro/tnels cardni. 

 Phyciodes tharos. 



Phyciodes batesii. 

 Danaus plexippus. 

 Everes comyntas. 

 Strymon melinus. 

 Strymon m^all)um. 



