American Classic Crossword «Source of formic acid»

 1  Kind of pond bloom

 6  Locates

12 Relating to the nervous system

14 Top-of-the-line

15 Prius maker

16 Cloth

17 Small lake

19 Blowgun missile

20 Workplace regulation agency

23 Plant from above the timber line

25 Half a Latin dance

26 Inner protective covering

28 "Get going!"

30 Provides input for an amp.

31 Speck

33 Mistakes

35 2,000 to a ton

36 Expurgator

38 Abnormal body sac

39 Small winning margin

40 Cataclysmic stellar explosion

42 The --- states, between Poland and Russia

44 More morose

48 Moonshot program

49 Remington ---, Pierce Brosnan role

50 Not often

51 Corpse

 1  Source of formic acid

 2  Fifth sign of the zodiac

 3  Fellow

 4  Odor

 5  Deceased

 6  Widely-used computer file type

 7  Preamble

 8  Republic east of the Adriatic

 9  At the moment

10 Way out

11 Dry wine

13 Tomb Raider --- Croft

18 "A Boy and his Dog" author Harlan ---

20 Adrian Monk's disorder

21 Card dispenser

22 Tint up top?

24 Photo

27 Sailors

29 Kind of bridge

30 E.g. Robinson, Doubtfire

32 Tucson time

34 Former Speaker "Tip" ---

37 Antarctic sea

38 Office in training

39 Wine valley

41 Tubs

42 Except

43 Overmodest

45 Agnus ---

46 Below 3 kilohertz

47 Sports official