BUTTERFLIES OF MESOPOTAMIA. 67 
Mesopotamia provides at least five food plants of machaon, three of 
them in great abundance, so that, with the vast extent of swamp in places 
somewhat like the Norfolk broads, and of plateaux, it is found commonly from 
near sea level by the rivers, to the highlands across the northern border. In early 
spring it is fond of cruising around the crests of stony hills or “‘ jebels ” and of 
settling at flowers or on the ground there. But it is most plentiful in May, 
about the banks and beds of the rivers and on the neighbouring plateaux where 
its food-plants abound. In April and May a low growing deep-yellow flowered 
rue is common on the table land at about 400 ft. elevation, the plant consisting 
mostly of the flower-sprays which grow to about a foot in height, each plant 
separately, but in groups forming yellow patches on the plateau. This plant 
was identified at Kew as Ruta tuberculata, Linne. The whole plant has an un- 
pleasant smell, and, when picked or handled, leaves as intensely bitter sub- 
stance on the fingers. It occurs less plentifully on the banks of the rivers. 
Larvee were most easily to be found by searching plants growing at the margin 
of old trenches. They were conspicuous and, as with all Papilio larve, extruded 
the orange-coloured osmeterium emitting a strong ‘Tom-cat’ like odour when 
disturbed. The larve fed on the flowers. As this plant began to go to seed, 
an umbellifer, Ammi majus, Linne, came into flower; and on this eggs were 
laid by machaon singly on flower buds at the margin of young flower-clusters. 
This plant was common about moist patches and in hollows ; and when young, 
is very slender, so that one saw a machaon repeatedly hovering about what 
at first appeared to be a grass-stem but on closer inspection proved to be an 
umbellifer. As this plant began to goto seed, another—identified at Kew as 
Ducrosia anethifolia, D. C.—which seemed to be local and not common, came 
into flower on the banks of the Dyala ; the leaves being rather stiff and a little 
like split miniature palm-leaves. The whole plant is a yellowish green, flowers 
paler, and all parts having an aromatic parsley or carrotlike smell. It grows 
in clumps and singly about conglomerate rock. 
Two larve only were found on this, both having remarkably white bands 
instead of yellowish or green ones, so that they were very conspicuous. While 
A. majus and this last mentioned plant were going over, a fourth food-plant, 
Ammi visnaga, Lam., had grown up among the first, especially in moist hollows 
on the banks and in the bed of the rivers and old canals. It is thick- 
stemmed, very erect, leaves made up of long filamentous branchings, the 
whole plant except the flowers being conspicuously deep green with compact 
umbrella like clusters of white flowers set more closely and uniformly together 
than those of A. majus; the pedicels being evenly arranged like numerous 
wires from the stem or stick of the umbrella. 
This plant continued in abundance and conspicuously green when in the middle 
of June A. majus and others had mostly withered to dry sticks. The larve 
fed on the flowers of all these food plants and scarcely ever on the leaves 
though Lt.-Col. W. H. Evans informs me that at Murree he has bred machaon 
“ on fennel-leaves not flowers.” 
Three of these food-plants grow in great abundance by the Dyala at about 
400 feet elevation, where 34 larve almost full grown were easily obtained on 
Ruta tuberculata within an hour. The extensive grass-fires which occur on 
these plateaux in the hot months must destroy vast numbers of eggs, larvae 
and pupz of butterflies and moths. 
A fifth food-plant an umbellifer, Feniculum vulgare, Gerta, was noted on 
May 2nd, 1920, at Baiji, having with its clusters of orange yellow flowers some 
general resemblance to rue. On some of these, near which a bleached machaon 
was seen, eggs of machaon were found laid singly, some on the lower and outer- 
side of the pedicels of the flowers; some about the middle, others close 
up below the florets, and one on a filament of a leaf arising by a flower-cluster. 
The eggs were semi-opaque pale green and mostly with a broad reddish brown 
