Confidence: It's likely to be this, but I can't be certain.
Notes: In Plate 3 of his book on Blowflies*, Zakaria Erzinclioglu, shows the heads of eight species; only in one case (Cynomya mortuorum), is the proboscis shown as having (a single) palp. From other images I have seen, the face here doesn’t look yellow enough for C. mortuorum.
*Naturalists Handbook No. 23 Richmond.